fix(edit): curate the CalDAV colour picker in painted space (#22)

The picker paints every swatch through pastelize, which pins lightness to
a constant and caps saturation — so the raw palette's lightness axis is
invisible on screen. Curating in raw space (as the first pass did) left
near-identical painted swatches (navy/blue/midnightblue all paint as one
mid blue) and stranded every neutral as an identical pale tint in a run of
"pinks" at the end of the grid.

Move dedup, thinning, and ordering into the painted (pastelised) space the
user actually sees: colours that paint identically collapse to one,
oversized palettes drop washed-out neutral-origin tints (painted chroma
below a floor) and thin by CIE76 ΔE in painted Lab, and the survivors sort
continuously by painted hue with the wheel cut at its widest gap. The CSS3
147-colour dump now lands at ~33 distinct, rainbow-ordered swatches with no
neutrals stranded at the end.

The hue/saturation shaping moves into a shared domain pastelArgb() so the
picker paints exactly what curation reasons about; ui/pastelize wraps it and
only picks the theme's brightness.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

CHANGELOG.md

@@ -5,6 +5,49 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Added
+- Set more than one default reminder per calendar. A calendar's default
+  reminders — and the global defaults under Settings → Notifications — can now
+  hold several lead times instead of just one, so new events can start with, say,
+  a reminder a week before *and* one on the day. The reminder pickers are now
+  multi-select; per-calendar overrides can still inherit the global default or
+  turn reminders off entirely. Thanks to @moonj for the suggestion ([#14]).
+- Widget headers now open the app. Tapping the month/year title on the month
+  widget opens the app on the month view, and tapping the "Upcoming" title on
+  the agenda widget opens it on your default view — so there's a one-tap way
+  back into the app that lands where you'd expect, instead of only through a day
+  or event. On the month widget, tapping anywhere on a day — not just the small
+  date number — now opens that day, and the "today" button snaps the grid back
+  to the current month in place. Thanks to @rgz46vic and @ptab for the
+  suggestions ([#18], [#20]).
+
+### Fixed
+- A tidy colour picker on CalDAV calendars. For calendars synced by a CalDAV
+  app (such as DAVx5), the event colour picker showed every colour the account
+  publishes — nearly 150 swatches in alphabetical order, many of them
+  duplicates or near-identical shades. The picker now shows only visually
+  distinct colours, arranged as a rainbow; near-duplicate shades and the
+  washed-out neutrals are folded away so no two swatches look alike. Picked
+  colours still sync exactly as before, and calendars with hand-picked
+  palettes (like Google's) are unaffected. Thanks to @ptab for the report
+  ([#22]).
+- Month widget arrows and "today" button work again. On release builds the
+  prev/next-month arrows and the jump-to-today control on the month widget did
+  nothing when tapped — code shrinking had stripped the tap handlers behind
+  them. They respond again. Thanks to @rgz46vic for the report ([#18]).
+- Disabled calendars no longer notify. Reminders for events in a calendar you
+  have disabled (Settings → Calendars) are now suppressed instead of still
+  popping up — matching how a disabled calendar's events already stay hidden
+  everywhere else in the app ([#17]).
+- Editing a single occurrence of a recurring event works again. Choosing **Only
+  this event** and saving a change to one event in a repeating series silently
+  did nothing — the change was rejected and the edit form simply reappeared with
+  nothing applied. The edited occurrence is now stored correctly, so the change
+  lands on just that one event and leaves the rest of the series untouched
+  ([#16]).
+
 ## [2.12.0] — 2026-06-28
 
 ### Added
@@ -729,3 +772,9 @@ automatically, with zero telemetry and no internet permission.
 [#10]: https://codeberg.org/jlmakiola/calendula/issues/10
 [#12]: https://codeberg.org/jlmakiola/calendula/issues/12
 [#13]: https://codeberg.org/jlmakiola/calendula/issues/13
+[#14]: https://codeberg.org/jlmakiola/calendula/issues/14
+[#16]: https://codeberg.org/jlmakiola/calendula/issues/16
+[#17]: https://codeberg.org/jlmakiola/calendula/issues/17
+[#18]: https://codeberg.org/jlmakiola/calendula/issues/18
+[#20]: https://codeberg.org/jlmakiola/calendula/issues/20
+[#22]: https://codeberg.org/jlmakiola/calendula/issues/22

app/build.gradle.kts

@@ -90,6 +90,8 @@ android {
 
     buildFeatures {
         compose = true
+        // BuildConfig.DEBUG gates the in-app debug ribbon (see DebugRibbon).
+        buildConfig = true
     }
 
     // Don't embed AGP's dependency-metadata block in the APK signing block. It's

app/proguard-rules.pro

@@ -16,6 +16,18 @@
 -keep class * extends androidx.room.RoomDatabase { *; }
 -dontwarn androidx.room.paging.**
 
+# Glance runs an @Composable's `actionRunCallback<T>()` by persisting the
+# callback's fully-qualified class name into the click PendingIntent, then
+# reflectively instantiating it (Class.forName(name).newInstance()) when the tap
+# fires. Under R8 full mode (AGP 9 default) these ActionCallback classes — only
+# ever referenced reflectively — get renamed or have their no-arg constructor
+# stripped, so the lookup fails silently and the tap does nothing. In the month
+# and agenda widgets that broke every run-callback control (the prev/next/today
+# month arrows and the agenda refresh) in release builds while actionStartActivity
+# taps, which ride a PendingIntent and need no reflection, kept working. Keep
+# every ActionCallback's name and constructor intact.
+-keep class * implements androidx.glance.appwidget.action.ActionCallback { <init>(...); }
+
 # WorkManager instantiates an InputMerger reflectively (Class.newInstance) from
 # the fully-qualified class name persisted in the WorkSpec, so the class must
 # keep both its name and a no-arg constructor. Glance renders every widget

app/src/debug/res/values/colors.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+    Debug-only launcher-icon background. Production is slate (#5C6B7A); the
+    debug build paints the adaptive-icon background burnt orange instead, so the
+    debug icon reads at a glance as "not the real app" on the home screen. The
+    off-white foreground mark contrasts on both. See drawable/ic_launcher_background.
+-->
+<resources>
+    <color name="ic_launcher_background">#FFB23B00</color>
+</resources>

app/src/debug/res/values/strings.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+    Debug-build resource overrides. Merged on top of src/main for the `debug`
+    build type only (release/releaseTest keep the production values), so the
+    debug app is unmistakable on the launcher: its own label, alongside the
+    real app thanks to the `.debug` applicationId suffix.
+-->
+<resources>
+    <string name="app_name">Calendula Debug</string>
+</resources>

app/src/main/java/de/jeanlucmakiola/calendula/MainActivity.kt

@@ -8,6 +8,7 @@ import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
 import androidx.appcompat.app.AppCompatActivity
 import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.runtime.CompositionLocalProvider
 import androidx.compose.runtime.getValue
@@ -29,6 +30,7 @@ import de.jeanlucmakiola.calendula.ui.common.LocalShowHourLines
 import de.jeanlucmakiola.calendula.ui.common.LocalUse24HourFormat
 import de.jeanlucmakiola.calendula.ui.WidgetNavRequest
 import de.jeanlucmakiola.calendula.ui.common.CalendarView
+import de.jeanlucmakiola.calendula.ui.common.DebugRibbon
 import de.jeanlucmakiola.calendula.ui.crash.CrashReportActivity
 import de.jeanlucmakiola.calendula.ui.crash.CrashReportDialog
 import de.jeanlucmakiola.calendula.ui.crash.submitCrashReport
@@ -101,19 +103,24 @@ class MainActivity : AppCompatActivity() {
                 darkTheme = darkTheme,
                 dynamicColor = settings.dynamicColor,
             ) {
-                CompositionLocalProvider(
-                    LocalUse24HourFormat provides use24Hour,
-                    LocalShowHourLines provides settings.showHourLines,
-                ) {
-                    RootScreen(
-                        modifier = Modifier.fillMaxSize(),
-                        requestedDetailKey = requestedDetailKey,
-                        onDetailKeyConsumed = { requestedDetailKey = null },
-                        widgetNavRequest = requestedNav,
-                        onWidgetNavConsumed = { requestedNav = null },
-                        requestedImportUri = requestedImportUri,
-                        onImportConsumed = { requestedImportUri = null },
-                    )
+                Box(modifier = Modifier.fillMaxSize()) {
+                    CompositionLocalProvider(
+                        LocalUse24HourFormat provides use24Hour,
+                        LocalShowHourLines provides settings.showHourLines,
+                    ) {
+                        RootScreen(
+                            modifier = Modifier.fillMaxSize(),
+                            requestedDetailKey = requestedDetailKey,
+                            onDetailKeyConsumed = { requestedDetailKey = null },
+                            widgetNavRequest = requestedNav,
+                            onWidgetNavConsumed = { requestedNav = null },
+                            requestedImportUri = requestedImportUri,
+                            onImportConsumed = { requestedImportUri = null },
+                        )
+                    }
+                    // A persistent corner marker so a debug build is never
+                    // mistaken for the production app; compiled out of release.
+                    if (BuildConfig.DEBUG) DebugRibbon()
                 }
                 pendingCrashReport?.let { report ->
                     CrashReportDialog(
@@ -186,6 +193,12 @@ class MainActivity : AppCompatActivity() {
         // An external date tap (launcher/clock) has no widget source, so it opens
         // the day view rooted over the default home view (OpenDate source = null).
         calendarTimeDateOrNull()?.let { return WidgetNavRequest.OpenDate(it.toString(), source = null) }
+        // A widget header tap: open a top-level view with no date drill-in. The
+        // empty string carried by [openViewIntent] means "the default home view".
+        if (hasExtra(EXTRA_OPEN_VIEW)) {
+            val name = getStringExtra(EXTRA_OPEN_VIEW).orEmpty()
+            return WidgetNavRequest.OpenView(CalendarView.entries.firstOrNull { it.name == name })
+        }
         val source = sourceViewOrNull()
         val eventId = getLongExtra(EXTRA_EVENT_ID, -1L)
         return when {
@@ -237,6 +250,10 @@ class MainActivity : AppCompatActivity() {
         private const val EXTRA_DATE_ISO = "de.jeanlucmakiola.calendula.extra.DATE_ISO"
         private const val EXTRA_CREATE = "de.jeanlucmakiola.calendula.extra.CREATE"
 
+        // A widget header tap asking to open a top-level view (no date drill-in).
+        // Its value is the target [CalendarView] name, or "" for the default view.
+        private const val EXTRA_OPEN_VIEW = "de.jeanlucmakiola.calendula.extra.OPEN_VIEW"
+
         // The [CalendarView] (by name) of the widget a launch came from. Roots the
         // in-app back stack in that view; absent for non-widget launches (reminders).
         private const val EXTRA_SOURCE_VIEW = "de.jeanlucmakiola.calendula.extra.SOURCE_VIEW"
@@ -300,5 +317,19 @@ class MainActivity : AppCompatActivity() {
                 putExtra(EXTRA_DATE_ISO, date.toString())
                 addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
             }
+
+        /**
+         * Open the app on a top-level [view] with no date drill-in — a widget
+         * header tap. A null [view] opens the user's default home view (the agenda
+         * widget's "Upcoming" title); a concrete view roots there over the default
+         * home (the month widget's month/year title → [CalendarView.Month]). The
+         * per-view data URI keeps distinct headers' PendingIntents from collapsing.
+         */
+        fun openViewIntent(context: Context, view: CalendarView?): Intent =
+            Intent(context, MainActivity::class.java).apply {
+                data = "calendula://view/${view?.name ?: "default"}".toUri()
+                putExtra(EXTRA_OPEN_VIEW, view?.name ?: "")
+                addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+            }
     }
 }

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/CalendarDataSource.kt

@@ -20,6 +20,7 @@ import de.jeanlucmakiola.calendula.domain.CalendarSource
 import de.jeanlucmakiola.calendula.domain.EventAttendee
 import de.jeanlucmakiola.calendula.domain.EventColorOption
 import de.jeanlucmakiola.calendula.domain.EventDetail
+import de.jeanlucmakiola.calendula.domain.curatedForPicker
 import de.jeanlucmakiola.calendula.domain.EventForm
 import de.jeanlucmakiola.calendula.domain.EventInstance
 import de.jeanlucmakiola.calendula.domain.EventStatus
@@ -57,7 +58,10 @@ interface CalendarDataSource {
 
     /**
      * The event-colour palette the calendar's account publishes
-     * (`CalendarContract.Colors`, `TYPE_EVENT`), sorted by key. Empty when the
+     * (`CalendarContract.Colors`, `TYPE_EVENT`), curated for display — deduped,
+     * thinned to visually distinct swatches when oversized (CalDAV adapters
+     * publish all ~147 CSS3 names, #22) and hue-sorted; see
+     * [curatedForPicker]. Empty when the
      * account exposes no palette (most local calendars, some CalDAV) — the
      * signal that a custom colour can only be written as a raw `EVENT_COLOR`,
      * which a synced calendar may drop on its next sync.
@@ -420,7 +424,7 @@ class AndroidCalendarDataSource @Inject constructor(
             c.mapAll { EventColorOption(key = it.getString(0).orEmpty(), argb = it.getInt(1)) }
         }
             ?.filter { it.key.isNotEmpty() }
-            ?.sortedBy { it.key }
+            ?.curatedForPicker()
             ?: emptyList()
     }
 

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/EventWriteMapper.kt

@@ -118,8 +118,14 @@ internal fun buildEventUpdateValues(
  * provider clone the series row and apply these on top. Unlike the series
  * update there is no dirty check — the exception is a fresh row, so every
  * form-backed column is written (empty optionals as explicit NULLs, since the
- * clone starts from the parent's values). An exception is a single event:
- * DTEND, never RRULE/DURATION.
+ * clone starts from the parent's values).
+ *
+ * The occurrence's length travels as DURATION, never DTEND: the provider
+ * rejects DTEND on an exception outright (`CalendarProvider2`:
+ * "Exceptions can't overwrite dtend") and derives the instance end from
+ * DTSTART + DURATION itself, clearing the inherited RRULE in the process. This
+ * matches how AOSP Calendar/Etar write exceptions; sending DTEND is what made
+ * "only this event" fail on-device (Codeberg #16).
  */
 internal fun buildOccurrenceExceptionValues(
     form: EventForm,
@@ -131,7 +137,7 @@ internal fun buildOccurrenceExceptionValues(
     put(CalendarContract.Events.TITLE, form.title.trim())
     put(CalendarContract.Events.ALL_DAY, if (form.isAllDay) 1 else 0)
     put(CalendarContract.Events.DTSTART, times.dtStartMillis)
-    put(CalendarContract.Events.DTEND, times.dtEndMillis)
+    put(CalendarContract.Events.DURATION, times.toRfc2445Duration(form.isAllDay))
     put(CalendarContract.Events.EVENT_TIMEZONE, times.timezone)
     put(CalendarContract.Events.AVAILABILITY, form.availability.toProviderValue())
     put(CalendarContract.Events.ACCESS_LEVEL, form.accessLevel.toProviderValue())

app/src/main/java/de/jeanlucmakiola/calendula/data/prefs/SettingsPrefs.kt

@@ -306,35 +306,36 @@ class SettingsPrefs @Inject constructor(
     }
 
     /**
-     * The default reminder lead time (minutes before start) prefilled on new
-     * **timed** events. `null` = no default reminder — the prior behaviour, kept
-     * as the factory default so existing users aren't surprised by reminders they
-     * never asked for. Stored as a string so "none" is distinct from a numeric
-     * value (and from an unset key, which is also "none"). Per-calendar overrides
-     * in [perCalendarReminderOverride] take precedence; all-day events instead use
+     * The default reminder lead times (minutes before start) prefilled on new
+     * **timed** events. The empty list = no default reminder — the prior
+     * behaviour, kept as the factory default so existing users aren't surprised by
+     * reminders they never asked for. Stored as a comma-joined list of minutes, or
+     * "none"/empty for no reminder (also the unset state). A legacy single value
+     * ("30") parses transparently to a one-element list. Per-calendar overrides in
+     * [perCalendarReminderOverride] take precedence; all-day events instead use
      * [defaultAllDayReminderMinutes]. Resolve with [resolveDefaultReminder].
      */
-    val defaultReminderMinutes: Flow<Int?> = store.data.map { prefs ->
-        prefs[DEFAULT_REMINDER_KEY].toReminderMinutes()
+    val defaultReminderMinutes: Flow<List<Int>> = store.data.map { prefs ->
+        prefs[DEFAULT_REMINDER_KEY].toReminderList()
     }
 
-    suspend fun setDefaultReminderMinutes(minutes: Int?) {
-        store.edit { it[DEFAULT_REMINDER_KEY] = minutes?.toString() ?: NONE }
+    suspend fun setDefaultReminderMinutes(minutes: List<Int>) {
+        store.edit { it[DEFAULT_REMINDER_KEY] = minutes.toStoredReminders() }
     }
 
     /**
-     * The default reminder lead time prefilled on new **all-day** events, in
+     * The default reminder lead times prefilled on new **all-day** events, in
      * minutes before the start of the day. All-day events want day-scale lead
      * times ("1 day before"), so they have their own default rather than reusing
-     * the timed one. `null` = no default. Per-calendar overrides do **not** apply
-     * to all-day events — they always use this global value.
+     * the timed one. Empty list = no default. Per-calendar overrides do **not**
+     * apply to all-day events — they always use this global value.
      */
-    val defaultAllDayReminderMinutes: Flow<Int?> = store.data.map { prefs ->
-        prefs[DEFAULT_ALLDAY_REMINDER_KEY].toReminderMinutes()
+    val defaultAllDayReminderMinutes: Flow<List<Int>> = store.data.map { prefs ->
+        prefs[DEFAULT_ALLDAY_REMINDER_KEY].toReminderList()
     }
 
-    suspend fun setDefaultAllDayReminderMinutes(minutes: Int?) {
-        store.edit { it[DEFAULT_ALLDAY_REMINDER_KEY] = minutes?.toString() ?: NONE }
+    suspend fun setDefaultAllDayReminderMinutes(minutes: List<Int>) {
+        store.edit { it[DEFAULT_ALLDAY_REMINDER_KEY] = minutes.toStoredReminders() }
     }
 
     /**
@@ -371,13 +372,13 @@ class SettingsPrefs @Inject constructor(
     /**
      * Per-calendar overrides of [defaultReminderMinutes] for **timed** events,
      * keyed by calendar id. A calendar **present** in the map overrides the global
-     * timed default for its new events: a `null` value means "no reminder", an int
-     * means that lead time. A calendar **absent** from the map inherits the global
-     * default. Serialised as `id=value;id=value`, with `none` for an explicit
-     * no-reminder override. (All-day events ignore this and use
-     * [defaultAllDayReminderMinutes].)
+     * timed default for its new events: an **empty** list means "no reminder", a
+     * non-empty list means those lead times. A calendar **absent** from the map
+     * inherits the global default. Serialised as `id=value;id=value`, where a value
+     * is a comma-joined minute list or `none` for an explicit no-reminder override.
+     * (All-day events ignore this and use [defaultAllDayReminderMinutes].)
      */
-    val perCalendarReminderOverride: Flow<Map<Long, Int?>> = store.data.map { prefs ->
+    val perCalendarReminderOverride: Flow<Map<Long, List<Int>>> = store.data.map { prefs ->
         parseReminderOverrides(prefs[CALENDAR_REMINDER_OVERRIDE_KEY])
     }
 
@@ -394,7 +395,7 @@ class SettingsPrefs @Inject constructor(
      * events, with the same semantics as [perCalendarReminderOverride] (absent =
      * inherit the global all-day default; present null = no reminder).
      */
-    val perCalendarAllDayReminderOverride: Flow<Map<Long, Int?>> = store.data.map { prefs ->
+    val perCalendarAllDayReminderOverride: Flow<Map<Long, List<Int>>> = store.data.map { prefs ->
         parseReminderOverrides(prefs[CALENDAR_ALLDAY_REMINDER_OVERRIDE_KEY])
     }
 
@@ -561,43 +562,46 @@ sealed interface CalendarReminderOverride {
     data object Inherit : CalendarReminderOverride
     /** Explicit "no reminder" for this calendar, regardless of the global default. */
     data object None : CalendarReminderOverride
-    /** A specific lead time in minutes before the event start. */
-    data class Minutes(val minutes: Int) : CalendarReminderOverride
+    /** Specific lead times in minutes before the event start (non-empty). */
+    data class Minutes(val minutes: List<Int>) : CalendarReminderOverride
 }
 
 /**
- * The lead time to prefill on a new event: the matching per-calendar override
+ * The lead times to prefill on a new event: the matching per-calendar override
  * if [calendarId] has one for this event kind, otherwise the global default for
  * that kind. All-day events consult [allDayOverrides] / [allDayGlobal]; timed
- * events consult [timedOverrides] / [timedGlobal]. `null` = no reminder. Pure so
- * it can be unit-tested.
+ * events consult [timedOverrides] / [timedGlobal]. The empty list = no reminder.
+ * Pure so it can be unit-tested.
  */
 fun resolveDefaultReminder(
-    timedGlobal: Int?,
-    allDayGlobal: Int?,
-    timedOverrides: Map<Long, Int?>,
-    allDayOverrides: Map<Long, Int?>,
+    timedGlobal: List<Int>,
+    allDayGlobal: List<Int>,
+    timedOverrides: Map<Long, List<Int>>,
+    allDayOverrides: Map<Long, List<Int>>,
     calendarId: Long?,
     isAllDay: Boolean,
-): Int? {
+): List<Int> {
     val overrides = if (isAllDay) allDayOverrides else timedOverrides
     val global = if (isAllDay) allDayGlobal else timedGlobal
     return if (calendarId != null && overrides.containsKey(calendarId)) {
-        overrides[calendarId]
+        overrides.getValue(calendarId)
     } else {
         global
     }
 }
 
-/** Apply a [CalendarReminderOverride] to an override map ([Inherit] removes the key). */
-private fun MutableMap<Long, Int?>.applyOverride(
+/**
+ * Apply a [CalendarReminderOverride] to an override map ([Inherit] removes the
+ * key; [None] and an empty [Minutes] both store the empty list).
+ */
+private fun MutableMap<Long, List<Int>>.applyOverride(
     calendarId: Long,
     override: CalendarReminderOverride,
 ) {
     when (override) {
         CalendarReminderOverride.Inherit -> remove(calendarId)
-        CalendarReminderOverride.None -> put(calendarId, null)
-        is CalendarReminderOverride.Minutes -> put(calendarId, override.minutes)
+        CalendarReminderOverride.None -> put(calendarId, emptyList())
+        is CalendarReminderOverride.Minutes -> put(calendarId, override.minutes.normalizeReminders())
     }
 }
 
@@ -623,24 +627,36 @@ private fun parseWeekStart(stored: String?): WeekStartPref = when (stored) {
 private const val NONE = "none"
 private const val ENTRY_SEP = ";"
 private const val KEY_VALUE_SEP = "="
+private const val LIST_SEP = ","
 
-private fun String?.toReminderMinutes(): Int? = when (this) {
-    null, "", NONE -> null
-    else -> toIntOrNull()
+/** Distinct, ascending lead times — the canonical form stored and resolved. */
+private fun List<Int>.normalizeReminders(): List<Int> = distinct().sorted()
+
+/**
+ * Parse a stored reminder value into lead times. `null`/empty/"none" → empty
+ * list; a comma-joined list → its minutes; a legacy single value ("30") → a
+ * one-element list. Non-numeric parts are dropped defensively.
+ */
+private fun String?.toReminderList(): List<Int> = when {
+    this == null || isEmpty() || this == NONE -> emptyList()
+    else -> split(LIST_SEP).mapNotNull { it.trim().toIntOrNull() }.normalizeReminders()
 }
 
-private fun parseReminderOverrides(stored: String?): Map<Long, Int?> {
+/** Serialise lead times for storage: "none" when empty, else comma-joined. */
+private fun List<Int>.toStoredReminders(): String =
+    if (isEmpty()) NONE else normalizeReminders().joinToString(LIST_SEP) { it.toString() }
+
+private fun parseReminderOverrides(stored: String?): Map<Long, List<Int>> {
     if (stored.isNullOrBlank()) return emptyMap()
     return stored.split(ENTRY_SEP).mapNotNull { entry ->
         val parts = entry.split(KEY_VALUE_SEP).takeIf { it.size == 2 } ?: return@mapNotNull null
         val id = parts[0].toLongOrNull() ?: return@mapNotNull null
-        val value = if (parts[1] == NONE) null else parts[1].toIntOrNull() ?: return@mapNotNull null
-        id to value
+        id to parts[1].toReminderList()
     }.toMap()
 }
 
-private fun serializeReminderOverrides(map: Map<Long, Int?>): String =
-    map.entries.joinToString(ENTRY_SEP) { (id, minutes) -> "$id$KEY_VALUE_SEP${minutes ?: NONE}" }
+private fun serializeReminderOverrides(map: Map<Long, List<Int>>): String =
+    map.entries.joinToString(ENTRY_SEP) { (id, minutes) -> "$id$KEY_VALUE_SEP${minutes.toStoredReminders()}" }
 
 private inline fun <reified E : Enum<E>> String?.toEnum(default: E): E =
     this?.let { stored -> enumValues<E>().firstOrNull { it.name == stored } } ?: default

app/src/main/java/de/jeanlucmakiola/calendula/data/reminders/EventReminderReceiver.kt

@@ -8,6 +8,7 @@ import android.content.pm.PackageManager
 import android.provider.CalendarContract
 import androidx.core.content.ContextCompat
 import dagger.hilt.android.AndroidEntryPoint
+import de.jeanlucmakiola.calendula.data.prefs.CalendarPrefs
 import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
@@ -16,6 +17,17 @@ import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.launch
 import javax.inject.Inject
 
+/**
+ * The due alerts that should actually surface as notifications: everything
+ * except alerts whose calendar the user has disabled in-app (mirroring the
+ * event filtering in CalendarRepositoryImpl). The caller still marks the full
+ * due set fired, so suppressed alerts are not re-broadcast by the provider.
+ */
+internal fun postableAlerts(
+    due: List<ReminderAlert>,
+    disabledCalendarIds: Set<Long>,
+): List<ReminderAlert> = due.filterNot { it.calendarId in disabledCalendarIds }
+
 /**
  * Becomes the app that turns the calendar provider's reminder alarms into
  * visible notifications (the Etar model — the provider broadcasts
@@ -32,6 +44,7 @@ class EventReminderReceiver : BroadcastReceiver() {
     @Inject lateinit var alertStore: ReminderAlertStore
     @Inject lateinit var notifier: ReminderNotifier
     @Inject lateinit var settingsPrefs: SettingsPrefs
+    @Inject lateinit var calendarPrefs: CalendarPrefs
 
     override fun onReceive(context: Context, intent: Intent) {
         if (intent.action != CalendarContract.ACTION_EVENT_REMINDER) return
@@ -46,7 +59,11 @@ class EventReminderReceiver : BroadcastReceiver() {
                 if (settingsPrefs.remindersEnabled.first()) {
                     val now = System.currentTimeMillis()
                     val due = alertStore.dueAlerts(now)
-                    due.forEach { notifier.post(it) }
+                    val disabled = calendarPrefs.disabledCalendarIds.first()
+                    // Suppress reminders for disabled calendars, but still mark
+                    // every due alert fired so the provider stops re-broadcasting
+                    // the suppressed ones.
+                    postableAlerts(due, disabled).forEach { notifier.post(it) }
                     alertStore.markFired(due.map { it.alertId }, now)
                 }
             } finally {

app/src/main/java/de/jeanlucmakiola/calendula/data/reminders/ReminderActionReceiver.kt

@@ -75,6 +75,7 @@ class ReminderActionReceiver : BroadcastReceiver() {
 
         private const val EXTRA_ALERT_ID = "alert_id"
         private const val EXTRA_EVENT_ID = "event_id"
+        private const val EXTRA_CALENDAR_ID = "calendar_id"
         private const val EXTRA_BEGIN = "begin"
         private const val EXTRA_END = "end"
         private const val EXTRA_TITLE = "title"
@@ -87,6 +88,7 @@ class ReminderActionReceiver : BroadcastReceiver() {
                 this.action = action
                 putExtra(EXTRA_ALERT_ID, alert.alertId)
                 putExtra(EXTRA_EVENT_ID, alert.eventId)
+                putExtra(EXTRA_CALENDAR_ID, alert.calendarId)
                 putExtra(EXTRA_BEGIN, alert.beginMillis)
                 putExtra(EXTRA_END, alert.endMillis)
                 putExtra(EXTRA_TITLE, alert.title)
@@ -113,6 +115,7 @@ class ReminderActionReceiver : BroadcastReceiver() {
             return ReminderAlert(
                 alertId = intent.getLongExtra(EXTRA_ALERT_ID, 0L),
                 eventId = intent.getLongExtra(EXTRA_EVENT_ID, 0L),
+                calendarId = intent.getLongExtra(EXTRA_CALENDAR_ID, 0L),
                 beginMillis = intent.getLongExtra(EXTRA_BEGIN, 0L),
                 endMillis = intent.getLongExtra(EXTRA_END, 0L),
                 title = intent.getStringExtra(EXTRA_TITLE).orEmpty(),

app/src/main/java/de/jeanlucmakiola/calendula/data/reminders/ReminderAlertStore.kt

@@ -16,6 +16,7 @@ import javax.inject.Singleton
 data class ReminderAlert(
     val alertId: Long,
     val eventId: Long,
+    val calendarId: Long,
     val beginMillis: Long,
     val endMillis: Long,
     /** Raw event title; may be blank — the notifier substitutes "(no title)". */
@@ -66,11 +67,12 @@ class AndroidReminderAlertStore @Inject constructor(
                     ReminderAlert(
                         alertId = c.getLong(0),
                         eventId = c.getLong(1),
-                        beginMillis = c.getLong(2),
-                        endMillis = c.getLong(3),
-                        title = c.getString(4).orEmpty(),
-                        location = c.getString(5)?.takeIf { it.isNotBlank() },
-                        isAllDay = c.getInt(6) == 1,
+                        calendarId = c.getLong(2),
+                        beginMillis = c.getLong(3),
+                        endMillis = c.getLong(4),
+                        title = c.getString(5).orEmpty(),
+                        location = c.getString(6)?.takeIf { it.isNotBlank() },
+                        isAllDay = c.getInt(7) == 1,
                     ),
                 )
             }
@@ -102,6 +104,7 @@ class AndroidReminderAlertStore @Inject constructor(
         val PROJECTION = arrayOf(
             CalendarContract.CalendarAlerts._ID,
             CalendarContract.CalendarAlerts.EVENT_ID,
+            CalendarContract.CalendarAlerts.CALENDAR_ID,
             CalendarContract.CalendarAlerts.BEGIN,
             CalendarContract.CalendarAlerts.END,
             CalendarContract.CalendarAlerts.TITLE,

app/src/main/java/de/jeanlucmakiola/calendula/domain/EventColorPalette.kt

@@ -0,0 +1,179 @@
+package de.jeanlucmakiola.calendula.domain
+
+import kotlin.math.abs
+import kotlin.math.atan2
+import kotlin.math.cbrt
+import kotlin.math.hypot
+import kotlin.math.pow
+import kotlin.math.roundToInt
+import kotlin.math.sqrt
+
+/**
+ * Curates an account's published event palette for the colour picker.
+ *
+ * Sync adapters differ wildly in what they publish: Google exposes a
+ * hand-picked two-dozen set, while CalDAV adapters (DAVx5) dump all ~147 CSS3
+ * named colours — including exact-value aliases (aqua/cyan, the gray/grey
+ * spelling pairs) and dozens of visually indistinguishable whites and grays
+ * (#22).
+ *
+ * Crucially, curation runs against the colour the picker actually *paints*, not
+ * the raw provider value. The picker softens every swatch through [pastelArgb]:
+ * it pins lightness to a constant and caps saturation, so the raw palette's
+ * lightness axis is invisible on screen. Two raw colours that look different —
+ * a navy and a mid blue — paint as one swatch, and every neutral (black, the
+ * grays, white) paints as the same pale tint. Judging distinctness in raw
+ * space, as before, left near-identical painted swatches and stranded the
+ * neutrals as a run of look-alike "pinks" at the end of the grid.
+ *
+ * Three steps, all in painted space:
+ *  1. Collapse swatches that paint identically to one (alphabetically-first key
+ *     wins, deterministically) — this folds aliases, dark/light shades of a
+ *     hue, and all the neutrals together.
+ *  2. Oversized palettes (> [CURATION_TRIGGER_SIZE]) drop the washed-out
+ *     neutral-origin tints (painted chroma < [PASTEL_CHROMA_FLOOR]) and are
+ *     then thinned to visually distinct colours: most vivid first, a colour is
+ *     kept only when at least [MIN_DELTA_E] (CIE76, painted Lab) from every
+ *     colour already kept. Small palettes are already curated by their adapter
+ *     and pass through whole.
+ *  3. The survivors are ordered like a rainbow — continuously by painted hue —
+ *     with the wheel cut at its single widest empty gap so the one unavoidable
+ *     seam lands in dead space and no hue family is torn across both ends.
+ *
+ * Every surviving option keeps its provider [EventColorOption.key], so a pick
+ * still round-trips through sync.
+ */
+fun List<EventColorOption>.curatedForPicker(): List<EventColorOption> {
+    val painted = sortedBy { it.key }
+        .distinctBy { pastelArgb(it.argb) }
+        .map { it to Lab.of(pastelArgb(it.argb)) }
+    val kept = if (painted.size <= CURATION_TRIGGER_SIZE) {
+        painted
+    } else {
+        thin(painted.filter { (_, lab) -> lab.chroma >= PASTEL_CHROMA_FLOOR })
+    }
+    return orderAroundWheel(kept).map { (option, _) -> option }
+}
+
+/**
+ * Orders swatches continuously around the (painted) hue wheel, then cuts the
+ * circle at its widest angular gap so the single seam lands in empty space
+ * instead of mid-family. Saturation breaks ties, vivid first.
+ */
+private fun orderAroundWheel(
+    swatches: List<Pair<EventColorOption, Lab>>,
+): List<Pair<EventColorOption, Lab>> {
+    if (swatches.size < 2) return swatches
+    val byHue = swatches.sortedWith(
+        compareBy({ (_, lab) -> lab.hue }, { (_, lab) -> -lab.chroma }),
+    )
+    // Split the wheel after the largest empty arc between neighbouring hues;
+    // the default is the wrap gap (last hue back round to the first), i.e. the
+    // familiar 0→360 order, and we only rotate away from it for a wider void.
+    var cutAfter = byHue.lastIndex
+    var widestGap = 360.0 - byHue.last().second.hue + byHue.first().second.hue
+    for (i in 0 until byHue.lastIndex) {
+        val gap = byHue[i + 1].second.hue - byHue[i].second.hue
+        if (gap > widestGap) {
+            widestGap = gap
+            cutAfter = i
+        }
+    }
+    return byHue.subList(cutAfter + 1, byHue.size) + byHue.subList(0, cutAfter + 1)
+}
+
+/** Greedy max-distance filter: vivid colours stake out clusters first. */
+private fun thin(
+    swatches: List<Pair<EventColorOption, Lab>>,
+): List<Pair<EventColorOption, Lab>> {
+    val byVividness = swatches
+        .sortedWith(compareByDescending<Pair<EventColorOption, Lab>> { it.second.chroma }.thenBy { it.first.key })
+    val kept = mutableListOf<Pair<EventColorOption, Lab>>()
+    for (candidate in byVividness) {
+        if (kept.none { it.second.deltaE(candidate.second) < MIN_DELTA_E }) kept += candidate
+    }
+    return kept
+}
+
+/**
+ * The softening the colour picker paints over every swatch (mirrored by
+ * ui/pastelize, which wraps this): keep the hue, scale and clamp saturation
+ * into a gentle band, and pin value to a constant so nothing screams and
+ * everything reads on the surface. Value is fixed here so curation is
+ * theme-independent — only hue and saturation distinguish painted swatches.
+ */
+fun pastelArgb(rawArgb: Int): Int {
+    val r = ((rawArgb shr 16) and 0xFF) / 255f
+    val g = ((rawArgb shr 8) and 0xFF) / 255f
+    val b = (rawArgb and 0xFF) / 255f
+    val max = maxOf(r, g, b)
+    val min = minOf(r, g, b)
+    val delta = max - min
+    val hue = when {
+        delta == 0f -> 0f
+        max == r -> 60f * (((g - b) / delta) % 6f)
+        max == g -> 60f * (((b - r) / delta) + 2f)
+        else -> 60f * (((r - g) / delta) + 4f)
+    }.let { if (it < 0f) it + 360f else it }
+    val sat = (if (max == 0f) 0f else delta / max) * 0.6f
+    val s = sat.coerceIn(0.25f, 0.65f)
+    val v = PASTEL_VALUE
+    val c = v * s
+    val x = c * (1f - abs((hue / 60f) % 2f - 1f))
+    val m = v - c
+    val (rr, gg, bb) = when {
+        hue < 60f -> Triple(c, x, 0f)
+        hue < 120f -> Triple(x, c, 0f)
+        hue < 180f -> Triple(0f, c, x)
+        hue < 240f -> Triple(0f, x, c)
+        hue < 300f -> Triple(x, 0f, c)
+        else -> Triple(c, 0f, x)
+    }
+    fun channel(value: Float) = ((value + m) * 255f).roundToInt().coerceIn(0, 255)
+    return (0xFF shl 24) or (channel(rr) shl 16) or (channel(gg) shl 8) or channel(bb)
+}
+
+/** Reference lightness for curation; the picker paints at this on dark surfaces. */
+private const val PASTEL_VALUE = 0.82f
+
+/** Palettes at most this big skip the thinning (Google's ~26 pass through). */
+private const val CURATION_TRIGGER_SIZE = 36
+
+/** Minimum CIE76 ΔE between surviving painted swatches. */
+private const val MIN_DELTA_E = 13.0
+
+/**
+ * Painted-chroma floor for oversized palettes: below this a swatch is a washed-
+ * out tint — the neutrals and near-whites the saturation clamp muddies — so it
+ * is dropped rather than shown as pale filler.
+ */
+private const val PASTEL_CHROMA_FLOOR = 22.0
+
+/** CIE Lab (D65) — the space where Euclidean distance ≈ perceived difference. */
+private class Lab(val l: Double, val a: Double, val b: Double) {
+    val chroma: Double get() = hypot(a, b)
+
+    /** Hue angle in degrees, 0–360, around the Lab a-b plane. */
+    val hue: Double get() = (Math.toDegrees(atan2(b, a)) + 360.0) % 360.0
+
+    fun deltaE(other: Lab): Double =
+        sqrt((l - other.l).pow(2) + (a - other.a).pow(2) + (b - other.b).pow(2))
+
+    companion object {
+        fun of(argb: Int): Lab {
+            fun linear(shift: Int): Double {
+                val c = ((argb shr shift) and 0xFF) / 255.0
+                return if (c <= 0.04045) c / 12.92 else ((c + 0.055) / 1.055).pow(2.4)
+            }
+            val r = linear(16)
+            val g = linear(8)
+            val b = linear(0)
+            val x = (0.4124 * r + 0.3576 * g + 0.1805 * b) / 0.95047
+            val y = 0.2126 * r + 0.7152 * g + 0.0722 * b
+            val z = (0.0193 * r + 0.1192 * g + 0.9505 * b) / 1.08883
+            fun f(t: Double) = if (t > 0.008856) cbrt(t) else 7.787 * t + 16.0 / 116.0
+            val fy = f(y)
+            return Lab(116 * fy - 16, 500 * (f(x) - fy), 200 * (fy - f(z)))
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/CalendarHost.kt

@@ -217,6 +217,17 @@ fun CalendarHost(
                 detailKey = key
                 onWidgetNavConsumed()
             }
+            is WidgetNavRequest.OpenView -> {
+                // A widget header tap: land on a top-level view with no date
+                // drill-in. Reveal it by dropping any covering overlay, then root
+                // the stack on the target (null → the default home) over the
+                // default home — so backing out returns to the default, then exits.
+                dismissCoveringOverlays()
+                createDateIso = null
+                pendingDayIso = null
+                viewStack = viewBaseStack(defaultView, req.view ?: defaultView)
+                onWidgetNavConsumed()
+            }
             is WidgetNavRequest.Create -> {
                 // External "new event" entries (QS tile / launcher shortcut /
                 // widget) must land on top of whatever is open — the form overlay

app/src/main/java/de/jeanlucmakiola/calendula/ui/WidgetNavRequest.kt

@@ -31,4 +31,13 @@ sealed interface WidgetNavRequest {
 
     /** Open the create-event form prefilled for [dateIso] (today when null). */
     data class Create(val dateIso: String?) : WidgetNavRequest
+
+    /**
+     * Open the app rooted on a top-level [view] with no date drill-in — a widget
+     * header tap. A null [view] means "the user's default home view" (the agenda
+     * widget's "Upcoming" title, issue #20); a concrete view roots there over the
+     * default home (the month widget's month/year title → [CalendarView.Month],
+     * issue #18), so backing out returns to the default view, then exits.
+     */
+    data class OpenView(val view: CalendarView?) : WidgetNavRequest
 }

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/CalendarColors.kt

@@ -15,17 +15,21 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.unit.dp
+import de.jeanlucmakiola.calendula.domain.pastelArgb
 
 /**
  * Soften a raw calendar color toward a pastel that fits the active theme.
  *  - Keeps the hue (so users still recognise their calendars)
  *  - Caps saturation so harsh provider colors stop screaming
  *  - Pins value/brightness to a band that reads on both light and dark surfaces
+ *
+ * The hue/saturation shaping lives in [pastelArgb] so the event-colour picker's
+ * curation reasons about the exact colour painted here (#22); this only picks
+ * the theme's brightness.
  */
 fun pastelize(rawArgb: Int, dark: Boolean): Color {
     val hsv = FloatArray(3)
-    android.graphics.Color.colorToHSV(rawArgb, hsv)
-    hsv[1] = (hsv[1] * 0.6f).coerceIn(0.25f, 0.65f)
+    android.graphics.Color.colorToHSV(pastelArgb(rawArgb), hsv)
     hsv[2] = if (dark) 0.82f else 0.72f
     return Color(android.graphics.Color.HSVToColor(hsv))
 }

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/DebugRibbon.kt

@@ -0,0 +1,50 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.BoxScope
+import androidx.compose.foundation.layout.offset
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.width
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.rotate
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import androidx.compose.ui.zIndex
+
+/**
+ * A Flutter-style "DEBUG" corner ribbon, drawn across the top-right corner of
+ * the app. Deliberately a stark, un-themed marker (not a product component) so a
+ * debug build is unmistakable at a glance — gate it on `BuildConfig.DEBUG` at the
+ * call site so it never reaches a release build. Non-interactive: it's a plain
+ * label with no pointer handler, so taps fall through to whatever is beneath it.
+ *
+ * Drop it in as the last child of a full-screen [androidx.compose.foundation.layout.Box]
+ * so it overlays the UI.
+ */
+@Composable
+fun BoxScope.DebugRibbon() {
+    Text(
+        text = "DEBUG",
+        color = Color.White,
+        fontSize = 10.sp,
+        fontWeight = FontWeight.Bold,
+        letterSpacing = 1.sp,
+        textAlign = TextAlign.Center,
+        modifier = Modifier
+            .align(Alignment.TopEnd)
+            .zIndex(1f)
+            // Push the band out so its midline crosses the very corner, then
+            // rotate it to the classic 45° ribbon.
+            .offset(x = 36.dp, y = 24.dp)
+            .rotate(45f)
+            .background(Color(0xFFB23B00))
+            .width(140.dp)
+            .padding(vertical = 2.dp),
+    )
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/Picker.kt

@@ -13,6 +13,7 @@ import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Check
+import androidx.compose.material3.Checkbox
 import androidx.compose.material3.FilledTonalButton
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
@@ -26,6 +27,7 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.SideEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
 import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
@@ -111,10 +113,15 @@ fun <T> OptionPicker(
 }
 
 /**
- * Reminder-default picker, full-screen: the grouped list (with an optional "Use
- * default reminder" row and a "None" row), the [presets] as lead-time rows, and
- * a "Custom" row that expands an inline number field plus a segmented unit
- * selector. Returns the choice as a [CalendarReminderOverride].
+ * Reminder-default picker, full-screen and **multi-select**: each [presets]
+ * lead time (plus any chosen custom value) is a checkbox row that toggles
+ * independently, so a default can carry several reminders ("1 week before" *and*
+ * "on the day"). A per-calendar picker ([allowInherit]) gains an exclusive "Use
+ * default reminder" row above the list; choosing it defers to the global default
+ * and clears the checked times. With nothing checked and inherit off, the choice
+ * is [CalendarReminderOverride.None] (an explicit no-reminder). A "Custom" row
+ * expands an inline number field plus a unit selector to add an arbitrary lead
+ * time to the set. Changes apply live via [onSelect]; the user leaves via back.
  */
 @Composable
 fun ReminderDefaultPicker(
@@ -125,57 +132,74 @@ fun ReminderDefaultPicker(
     onSelect: (CalendarReminderOverride) -> Unit,
     onDismiss: () -> Unit,
 ) {
-    val selectedMinutes = (selected as? CalendarReminderOverride.Minutes)?.minutes
-    val customSelected = selectedMinutes != null && selectedMinutes !in presets
-    val seed = decomposeReminder(selectedMinutes?.takeIf { customSelected })
+    // Optimistic local state: the chosen override is authoritative while the
+    // picker is open, so quick successive toggles compose on each other instead
+    // of racing the round-trip through the settings flow (which would drop a
+    // toggle made before the previous write echoes back). Seeded once on open;
+    // the picker leaves composition on dismiss, so reopening re-reads [selected].
+    var current by remember { mutableStateOf(selected) }
+    val inherits = current is CalendarReminderOverride.Inherit
+    val selectedMinutes = (current as? CalendarReminderOverride.Minutes)?.minutes.orEmpty()
+    // Presets plus any selected custom (non-preset) values, each as its own row.
+    val rows = presets + selectedMinutes.filter { it !in presets }.sorted()
 
     var customExpanded by rememberSaveable { mutableStateOf(false) }
-    var amountText by rememberSaveable { mutableStateOf(seed.first) }
-    var unit by rememberSaveable { mutableStateOf(seed.second) }
+    var amountText by rememberSaveable { mutableStateOf("") }
+    var unit by rememberSaveable { mutableStateOf(ReminderUnit.Minutes) }
 
-    val options = buildList {
-        if (allowInherit) add(CalendarReminderOverride.Inherit)
-        add(CalendarReminderOverride.None)
-        presets.forEach { add(CalendarReminderOverride.Minutes(it)) }
+    fun apply(override: CalendarReminderOverride) {
+        current = override
+        onSelect(override)
     }
-    val rowCount = options.size + 1 // + the custom row
+    // Emit the override for a new set of minutes: empty collapses to None, which
+    // (with inherit unchosen) reads as an explicit "no reminder".
+    fun emit(minutes: List<Int>) {
+        val norm = minutes.distinct().sorted()
+        apply(
+            if (norm.isEmpty()) {
+                CalendarReminderOverride.None
+            } else {
+                CalendarReminderOverride.Minutes(norm)
+            },
+        )
+    }
+    fun toggle(minute: Int) =
+        emit(if (minute in selectedMinutes) selectedMinutes - minute else selectedMinutes + minute)
 
     FullScreenPicker(title = title, onDismiss = onDismiss) {
-        options.forEachIndexed { index, option ->
-            val isSelected = option == selected
+        // Exclusive "use default" choice (per-calendar only): its own group above
+        // the multi-select list, since inheriting is mutually exclusive with
+        // picking specific times.
+        if (allowInherit) {
             GroupedRow(
-                title = reminderOverrideLabel(option),
-                position = positionOf(index, rowCount),
-                selected = isSelected,
-                trailing = if (isSelected) {
+                title = stringResource(R.string.reminder_use_default),
+                position = Position.Alone,
+                selected = inherits,
+                trailing = if (inherits) {
                     { SelectedCheck() }
                 } else {
                     null
                 },
-                onClick = {
-                    onSelect(option)
-                    onDismiss()
-                },
+                onClick = { apply(CalendarReminderOverride.Inherit) },
+            )
+            Spacer(Modifier.height(24.dp))
+        }
+        val rowCount = rows.size + 1 // + the custom row
+        rows.forEachIndexed { index, minute ->
+            val checked = minute in selectedMinutes
+            GroupedRow(
+                title = reminderLeadTimeLabel(minute),
+                position = positionOf(index, rowCount),
+                selected = checked,
+                trailing = { Checkbox(checked = checked, onCheckedChange = { toggle(minute) }) },
+                onClick = { toggle(minute) },
             )
         }
         // When expanded, the Custom row connects downward into the editor card
         // so the two read as one grouped container (the per-calendar pattern).
         GroupedRow(
-            title = if (customSelected) {
-                stringResource(
-                    R.string.reminder_custom_with_value,
-                    reminderLeadTimeLabel(selectedMinutes!!),
-                )
-            } else {
-                stringResource(R.string.event_edit_reminder_custom)
-            },
-            position = if (customExpanded) Position.Top else positionOf(options.size, rowCount),
-            selected = customSelected,
-            trailing = if (customSelected) {
-                { SelectedCheck() }
-            } else {
-                null
-            },
+            title = stringResource(R.string.event_edit_reminder_custom),
+            position = if (customExpanded) Position.Top else positionOf(rows.size, rowCount),
             onClick = { customExpanded = !customExpanded },
         )
         AnimatedVisibility(
@@ -189,8 +213,9 @@ fun ReminderDefaultPicker(
                 unit = unit,
                 onUnitChange = { unit = it },
                 onConfirm = { minutes ->
-                    onSelect(CalendarReminderOverride.Minutes(minutes))
-                    onDismiss()
+                    emit(selectedMinutes + minutes)
+                    amountText = ""
+                    customExpanded = false
                 },
             )
         }
@@ -428,18 +453,3 @@ fun agendaRangeLabel(range: AgendaRange): String = when (range) {
     is AgendaRange.Custom -> pluralStringResource(R.plurals.agenda_range_days, range.days, range.days)
 }
 
-@Composable
-private fun reminderOverrideLabel(override: CalendarReminderOverride): String = when (override) {
-    CalendarReminderOverride.Inherit -> stringResource(R.string.reminder_use_default)
-    CalendarReminderOverride.None -> stringResource(R.string.reminder_none)
-    is CalendarReminderOverride.Minutes -> reminderLeadTimeLabel(override.minutes)
-}
-
-/** Seed the custom editor: the largest exact unit for [minutes] (null → empty). */
-private fun decomposeReminder(minutes: Int?): Pair<String, ReminderUnit> = when {
-    minutes == null -> "" to ReminderUnit.Minutes
-    minutes % 10_080 == 0 -> (minutes / 10_080).toString() to ReminderUnit.Weeks
-    minutes % 1_440 == 0 -> (minutes / 1_440).toString() to ReminderUnit.Days
-    minutes % 60 == 0 -> (minutes / 60).toString() to ReminderUnit.Hours
-    else -> minutes.toString() to ReminderUnit.Minutes
-}

app/src/main/java/de/jeanlucmakiola/calendula/ui/edit/EventEditScreen.kt

@@ -1712,12 +1712,20 @@ private fun ColorPickerDialog(
         text = {
             Column(verticalArrangement = Arrangement.spacedBy(12.dp)) {
                 if (palette.isNotEmpty()) {
+                    // The event's current colour may not be in the curated
+                    // palette (thinned near-duplicate, or a raw colour set
+                    // elsewhere) — append it so the selection ring has a home.
+                    val swatches = palette.map { it.argb }.let {
+                        if (selected != null && selected !in it) it + selected else it
+                    }
                     ColorSwatchRow(
-                        colors = palette.map { it.argb },
+                        colors = swatches,
                         selected = selected,
                         onSelect = { argb ->
-                            palette.firstOrNull { it.argb == argb }
-                                ?.let { onPickKey(it.key, it.argb) }
+                            val option = palette.firstOrNull { it.argb == argb }
+                            // The appended current colour has no key to write —
+                            // it is already the event's colour, so just close.
+                            if (option != null) onPickKey(option.key, option.argb) else onDismiss()
                         },
                         dark = dark,
                     )

app/src/main/java/de/jeanlucmakiola/calendula/ui/edit/EventEditViewModel.kt

@@ -108,10 +108,10 @@ class EventEditViewModel @Inject constructor(
     )
 
     private data class ReminderDefaults(
-        val timed: Int?,
-        val allDay: Int?,
-        val timedOverrides: Map<Long, Int?>,
-        val allDayOverrides: Map<Long, Int?>,
+        val timed: List<Int>,
+        val allDay: List<Int>,
+        val timedOverrides: Map<Long, List<Int>>,
+        val allDayOverrides: Map<Long, List<Int>>,
     )
 
     private data class ExternalInputs(
@@ -260,7 +260,7 @@ class EventEditViewModel @Inject constructor(
             // Re-check after suspending: bail if the form closed or the user edited.
             val form = _form.value ?: return@launch
             if (_editTarget.value != null || _remindersTouched.value) return@launch
-            val default = resolveDefaultReminder(
+            val reminders = resolveDefaultReminder(
                 timedGlobal = defaults.timed,
                 allDayGlobal = defaults.allDay,
                 timedOverrides = defaults.timedOverrides,
@@ -268,7 +268,6 @@ class EventEditViewModel @Inject constructor(
                 calendarId = targetId,
                 isAllDay = form.isAllDay,
             )
-            val reminders = listOfNotNull(default)
             _form.value = form.copy(reminders = reminders)
             // Surface the section so an auto-applied default is visible and
             // removable, even when Reminders isn't a default-shown field.

app/src/main/java/de/jeanlucmakiola/calendula/ui/settings/SettingsScreen.kt

@@ -1115,7 +1115,7 @@ private fun NotificationsScreen(
             presets = REMINDER_PRESETS,
             selected = state.defaultReminderMinutes.toReminderChoice(),
             allowInherit = false,
-            onSelect = { viewModel.setDefaultReminderMinutes(it.toMinutesOrNull()) },
+            onSelect = { viewModel.setDefaultReminderMinutes(it.toMinutesList()) },
             onDismiss = { showDefaultReminder = false },
         )
     }
@@ -1125,7 +1125,7 @@ private fun NotificationsScreen(
             presets = ALLDAY_REMINDER_PRESETS,
             selected = state.defaultAllDayReminderMinutes.toReminderChoice(),
             allowInherit = false,
-            onSelect = { viewModel.setDefaultAllDayReminderMinutes(it.toMinutesOrNull()) },
+            onSelect = { viewModel.setDefaultAllDayReminderMinutes(it.toMinutesList()) },
             onDismiss = { showAllDayReminder = false },
         )
     }
@@ -1174,13 +1174,13 @@ private fun NotificationsScreen(
 /** Which calendar + event kind a per-calendar reminder-override dialog targets. */
 private data class OverrideTarget(val calendarId: Long, val isAllDay: Boolean)
 
-/** A global default (null = none) as a picker choice for selection highlighting. */
-private fun Int?.toReminderChoice(): CalendarReminderOverride =
-    if (this == null) CalendarReminderOverride.None else CalendarReminderOverride.Minutes(this)
+/** A global default (empty = none) as a picker choice for selection highlighting. */
+private fun List<Int>.toReminderChoice(): CalendarReminderOverride =
+    if (isEmpty()) CalendarReminderOverride.None else CalendarReminderOverride.Minutes(this)
 
 /** A picked choice as global-default minutes (Inherit isn't offered for globals). */
-private fun CalendarReminderOverride.toMinutesOrNull(): Int? =
-    (this as? CalendarReminderOverride.Minutes)?.minutes
+private fun CalendarReminderOverride.toMinutesList(): List<Int> =
+    (this as? CalendarReminderOverride.Minutes)?.minutes ?: emptyList()
 
 /**
  * Whether Calendula is exempt from battery optimisation, re-read on every
@@ -1255,27 +1255,33 @@ private fun formatTimeOfDay(context: Context, minutesOfDay: Int): String {
 }
 
 /** The stored override for [calendarId], as a picker choice (absent → inherit). */
-private fun Map<Long, Int?>.choiceFor(calendarId: Long): CalendarReminderOverride = when {
+private fun Map<Long, List<Int>>.choiceFor(calendarId: Long): CalendarReminderOverride = when {
     !containsKey(calendarId) -> CalendarReminderOverride.Inherit
-    this[calendarId] == null -> CalendarReminderOverride.None
-    else -> CalendarReminderOverride.Minutes(this.getValue(calendarId)!!)
+    this.getValue(calendarId).isEmpty() -> CalendarReminderOverride.None
+    else -> CalendarReminderOverride.Minutes(this.getValue(calendarId))
 }
 
-/** Label for a global-default choice: null → "None", else the lead time. */
+/** Label for a global-default choice: empty → "None", else the lead times joined. */
 @Composable
-private fun reminderChoiceLabel(minutes: Int?): String =
-    if (minutes == null) stringResource(R.string.reminder_none) else reminderLeadTimeLabel(minutes)
+private fun reminderChoiceLabel(minutes: List<Int>): String {
+    if (minutes.isEmpty()) return stringResource(R.string.reminder_none)
+    // reminderLeadTimeLabel is @Composable, so resolve each part in a loop rather
+    // than a (non-composable) joinToString transform.
+    val parts = ArrayList<String>(minutes.size)
+    for (m in minutes) parts.add(reminderLeadTimeLabel(m))
+    return parts.joinToString(", ")
+}
 
 /** Row summary for a calendar: its override, or the inherited global default. */
 @Composable
 private fun calendarOverrideSummary(
     choice: CalendarReminderOverride,
-    globalDefault: Int?,
+    globalDefault: List<Int>,
 ): String = when (choice) {
     CalendarReminderOverride.Inherit ->
         stringResource(R.string.settings_calendar_reminder_inherits, reminderChoiceLabel(globalDefault))
     CalendarReminderOverride.None -> stringResource(R.string.reminder_none)
-    is CalendarReminderOverride.Minutes -> reminderLeadTimeLabel(choice.minutes)
+    is CalendarReminderOverride.Minutes -> reminderChoiceLabel(choice.minutes)
 }
 
 // ---------------------------------------------------------------------------

app/src/main/java/de/jeanlucmakiola/calendula/ui/settings/SettingsUiState.kt

@@ -50,24 +50,24 @@ data class SettingsUiState(
     /** Whether Calendula posts reminder notifications (v1.4). */
     val remindersEnabled: Boolean = true,
     /**
-     * The default reminder lead time (minutes) prefilled on new timed events;
-     * null = no default reminder. Per-calendar overrides take precedence.
+     * The default reminder lead times (minutes) prefilled on new timed events;
+     * empty = no default reminder. Per-calendar overrides take precedence.
      */
-    val defaultReminderMinutes: Int? = null,
-    /** The default reminder lead time prefilled on new all-day events; null = none. */
-    val defaultAllDayReminderMinutes: Int? = null,
+    val defaultReminderMinutes: List<Int> = emptyList(),
+    /** The default reminder lead times prefilled on new all-day events; empty = none. */
+    val defaultAllDayReminderMinutes: List<Int> = emptyList(),
     /** Wall-clock time (minutes from midnight) all-day reminders fire at; default 09:00. */
     val allDayReminderTimeMinutes: Int = SettingsPrefs.DEFAULT_ALLDAY_REMINDER_TIME,
     /** How long the notification "Snooze" action defers a reminder; default 10 min. */
     val snoozeMinutes: Int = SettingsPrefs.DEFAULT_SNOOZE_MINUTES,
     /**
      * Per-calendar overrides of [defaultReminderMinutes] for timed events: a
-     * calendar present in the map overrides the global default (null value = no
+     * calendar present in the map overrides the global default (empty value = no
      * reminder); absent = inherit the global default.
      */
-    val perCalendarReminderOverride: Map<Long, Int?> = emptyMap(),
+    val perCalendarReminderOverride: Map<Long, List<Int>> = emptyMap(),
     /** Per-calendar overrides of [defaultAllDayReminderMinutes] for all-day events. */
-    val perCalendarAllDayReminderOverride: Map<Long, Int?> = emptyMap(),
+    val perCalendarAllDayReminderOverride: Map<Long, List<Int>> = emptyMap(),
     /** Writable calendars, shown as per-calendar reminder-override rows. */
     val writableCalendars: List<CalendarSource> = emptyList(),
     /**

app/src/main/java/de/jeanlucmakiola/calendula/ui/settings/SettingsViewModel.kt

@@ -148,15 +148,15 @@ class SettingsViewModel @Inject constructor(
 
     private data class ReminderDefaults(
         val allowColor: Boolean,
-        val defaultReminder: Int?,
-        val allDayReminder: Int?,
+        val defaultReminder: List<Int>,
+        val allDayReminder: List<Int>,
         val allDayReminderTime: Int,
         val snoozeMinutes: Int,
     )
 
     private data class ReminderOverrides(
-        val timed: Map<Long, Int?>,
-        val allDay: Map<Long, Int?>,
+        val timed: Map<Long, List<Int>>,
+        val allDay: Map<Long, List<Int>>,
         val calendars: List<CalendarSource>,
     )
 
@@ -278,11 +278,11 @@ class SettingsViewModel @Inject constructor(
         viewModelScope.launch { prefs.setAutofocusEventTitle(enabled) }
     }
 
-    fun setDefaultReminderMinutes(minutes: Int?) {
+    fun setDefaultReminderMinutes(minutes: List<Int>) {
         viewModelScope.launch { prefs.setDefaultReminderMinutes(minutes) }
     }
 
-    fun setDefaultAllDayReminderMinutes(minutes: Int?) {
+    fun setDefaultAllDayReminderMinutes(minutes: List<Int>) {
         viewModelScope.launch { prefs.setDefaultAllDayReminderMinutes(minutes) }
     }
 

app/src/main/java/de/jeanlucmakiola/calendula/widget/agenda/AgendaWidget.kt

@@ -193,6 +193,8 @@ private fun AgendaHeader() {
         modifier = GlanceModifier.fillMaxWidth().padding(horizontal = 4.dp),
         verticalAlignment = Alignment.CenterVertically,
     ) {
+        // Tap the "Upcoming" title to open the app on the user's default view
+        // (issue #20) — a null target resolves to the default home in the host.
         Text(
             text = context.getString(R.string.widget_agenda_title),
             style = TextStyle(
@@ -200,7 +202,11 @@ private fun AgendaHeader() {
                 fontSize = 16.sp,
                 fontWeight = FontWeight.Medium,
             ),
-            modifier = GlanceModifier.defaultWeight(),
+            modifier = GlanceModifier
+                .defaultWeight()
+                .clickable(
+                    actionStartActivity(MainActivity.openViewIntent(context, view = null)),
+                ),
         )
         IconButton(
             resId = R.drawable.ic_widget_refresh,

app/src/main/java/de/jeanlucmakiola/calendula/widget/month/MonthWidget.kt

@@ -194,6 +194,8 @@ private fun MonthHeader(label: String) {
                 ),
             ),
         )
+        // Tap the month/year title to open the app on the month view (issue #18),
+        // rooted over the default home so backing out returns there.
         Text(
             text = label,
             style = TextStyle(
@@ -204,16 +206,17 @@ private fun MonthHeader(label: String) {
             ),
             modifier = GlanceModifier
                 .defaultWeight()
-                .clickable(actionRunCallback<ResetMonthAction>()),
+                .clickable(
+                    actionStartActivity(
+                        MainActivity.openViewIntent(context, CalendarView.Month),
+                    ),
+                ),
         )
+        // The "today" button snaps the grid back to the current month in place.
         HeaderIcon(
             resId = R.drawable.ic_widget_today,
             contentDescription = context.getString(R.string.widget_today),
-            onClick = GlanceModifier.clickable(
-                actionStartActivity(
-                    MainActivity.openDateIntent(context, today(systemZone()), CalendarView.Month),
-                ),
-            ),
+            onClick = GlanceModifier.clickable(actionRunCallback<ResetMonthAction>()),
         )
         HeaderIcon(
             resId = R.drawable.ic_widget_chevron_right,
@@ -301,6 +304,15 @@ private fun WeekRow(
     }
 }
 
+/**
+ * Open [date]'s day view rooted in the month view (so back returns to the month
+ * grid) — the same target the in-app month grid uses when a day cell is tapped.
+ * Shared by every tappable part of a day column so, as in the app, a tap anywhere
+ * on a day opens it; only an event bar on top opts out to open its own detail.
+ */
+private fun openDayAction(context: Context, date: LocalDate) =
+    actionStartActivity(MainActivity.openDateIntent(context, date, CalendarView.Month))
+
 @Composable
 private fun DayNumber(date: LocalDate, isToday: Boolean, inMonth: Boolean, colW: Dp) {
     val context = LocalContext.current
@@ -308,11 +320,7 @@ private fun DayNumber(date: LocalDate, isToday: Boolean, inMonth: Boolean, colW:
         modifier = GlanceModifier
             .width(colW)
             .height(DAY_NUMBER_HEIGHT)
-            // Tap a day number to open that day, rooted in the month view so back
-            // returns to the month grid.
-            .clickable(
-                actionStartActivity(MainActivity.openDateIntent(context, date, CalendarView.Month)),
-            ),
+            .clickable(openDayAction(context, date)),
         contentAlignment = Alignment.Center,
     ) {
         Box(
@@ -339,6 +347,7 @@ private fun DayNumber(date: LocalDate, isToday: Boolean, inMonth: Boolean, colW:
 
 @Composable
 private fun LaneRow(week: MonthWeek, lane: Int, dark: Boolean, colW: Dp) {
+    val context = LocalContext.current
     Row(modifier = GlanceModifier.fillMaxWidth()) {
         var col = 0
         while (col < 7) {
@@ -352,7 +361,14 @@ private fun LaneRow(week: MonthWeek, lane: Int, dark: Boolean, colW: Dp) {
                 if (timed != null) {
                     SpanBar(event = timed, dark = dark, width = colW)
                 } else {
-                    Box(GlanceModifier.width(colW).height(LANE_HEIGHT)) {}
+                    // Empty lane cell: a tap opens that day, so blank space in a
+                    // day column is a day-open target just like the number is.
+                    Box(
+                        GlanceModifier
+                            .width(colW)
+                            .height(LANE_HEIGHT)
+                            .clickable(openDayAction(context, week.days[col])),
+                    ) {}
                 }
                 col += 1
             }
@@ -401,14 +417,20 @@ private fun SpanBar(event: EventInstance, dark: Boolean, width: Dp) {
 
 @Composable
 private fun OverflowRow(week: MonthWeek, colW: Dp) {
+    val context = LocalContext.current
     Row(modifier = GlanceModifier.fillMaxWidth()) {
         week.days.forEachIndexed { col, date ->
             val shownSpans = week.spans.count { col in it.startCol..it.endCol && it.lane < MAX_LANES }
             val freeSlots = (MAX_LANES - shownSpans).coerceAtLeast(0)
             val timedShown = minOf(freeSlots, week.timedByDay[date].orEmpty().size)
             val hidden = (week.countByDay[date] ?: 0) - shownSpans - timedShown
+            // The overflow row is part of the day column too: tapping it (whether
+            // it shows "+N" or is blank) opens that day, same as the app.
             Box(
-                modifier = GlanceModifier.width(colW).height(LANE_HEIGHT),
+                modifier = GlanceModifier
+                    .width(colW)
+                    .height(LANE_HEIGHT)
+                    .clickable(openDayAction(context, date)),
                 contentAlignment = Alignment.CenterStart,
             ) {
                 if (hidden > 0) {

app/src/main/res/values-de/strings.xml

@@ -295,7 +295,6 @@
     <string name="reminder_none">Keine</string>
     <string name="reminder_use_default">Standard-Erinnerung verwenden</string>
     <string name="reminder_custom_amount">Anzahl</string>
-    <string name="reminder_custom_with_value">Benutzerdefiniert (%1$s)</string>
     <string name="reminder_custom_set">Übernehmen</string>
     <string name="settings_calendar_reminders_hint">Standard pro Kalender überschreiben — getrennt für Termine mit Uhrzeit und ganztägige Termine. Ein Kalender kann den Standard übernehmen, weglassen oder einen eigenen festlegen.</string>
     <string name="settings_calendar_reminder_inherits">Standard (%1$s)</string>

app/src/main/res/values/strings.xml

@@ -330,7 +330,6 @@
     <string name="reminder_none">None</string>
     <string name="reminder_use_default">Use default reminder</string>
     <string name="reminder_custom_amount">Amount</string>
-    <string name="reminder_custom_with_value">Custom (%1$s)</string>
     <string name="reminder_custom_set">Set</string>
     <string name="settings_calendar_reminders_title">Per-calendar reminders</string>
     <string name="settings_calendar_reminders_hint">Override the default per calendar — separately for timed and all-day events. A calendar can keep the default, drop it, or set its own.</string>

app/src/test/java/de/jeanlucmakiola/calendula/data/calendar/EventWriteMapperTest.kt

@@ -199,11 +199,12 @@ class EventWriteMapperTest {
         assertThat(values[CalendarContract.Events.TITLE]).isEqualTo("Moved")
         assertThat(values[CalendarContract.Events.EVENT_LOCATION]).isEqualTo("Berlin")
         assertThat(values[CalendarContract.Events.DTSTART]).isEqualTo(1_781_164_800_000L)
-        assertThat(values[CalendarContract.Events.DTEND])
-            .isEqualTo(1_781_164_800_000L + 5_400_000L)
-        // A single occurrence never carries its own rule.
+        // The occurrence's length travels as DURATION, never DTEND — the provider
+        // rejects DTEND on an exception ("Exceptions can't overwrite dtend") and
+        // derives the end from DTSTART + DURATION, clearing the inherited RRULE.
+        assertThat(values[CalendarContract.Events.DURATION]).isEqualTo("P5400S")
+        assertThat(values).doesNotContainKey(CalendarContract.Events.DTEND)
         assertThat(values).doesNotContainKey(CalendarContract.Events.RRULE)
-        assertThat(values).doesNotContainKey(CalendarContract.Events.DURATION)
     }
 
     @Test

app/src/test/java/de/jeanlucmakiola/calendula/data/prefs/SettingsPrefsTest.kt

@@ -258,22 +258,38 @@ class SettingsPrefsTest {
     }
 
     @Test
-    fun `default reminder is none until set`(@TempDir tempDir: Path) = runTest {
+    fun `default reminder is empty until set`(@TempDir tempDir: Path) = runTest {
         val prefs = SettingsPrefs(newDataStore(tempDir))
-        assertThat(prefs.defaultReminderMinutes.first()).isNull()
+        assertThat(prefs.defaultReminderMinutes.first()).isEmpty()
     }
 
     @Test
-    fun `default reminder round-trips, including none`(@TempDir tempDir: Path) = runTest {
+    fun `default reminder round-trips none, single, and multiple lead times`(@TempDir tempDir: Path) = runTest {
         val prefs = SettingsPrefs(newDataStore(tempDir))
-        prefs.setDefaultReminderMinutes(30)
-        assertThat(prefs.defaultReminderMinutes.first()).isEqualTo(30)
-        prefs.setDefaultReminderMinutes(null)
-        assertThat(prefs.defaultReminderMinutes.first()).isNull()
+        prefs.setDefaultReminderMinutes(listOf(30))
+        assertThat(prefs.defaultReminderMinutes.first()).containsExactly(30)
+        // Several lead times persist, normalised to distinct ascending order.
+        prefs.setDefaultReminderMinutes(listOf(10_080, 0, 30, 30))
+        assertThat(prefs.defaultReminderMinutes.first()).containsExactly(0, 30, 10_080).inOrder()
+        prefs.setDefaultReminderMinutes(emptyList())
+        assertThat(prefs.defaultReminderMinutes.first()).isEmpty()
     }
 
     @Test
-    fun `garbage stored default reminder reads as none`(@TempDir tempDir: Path) = runTest {
+    fun `legacy single-value default reminder parses as a one-element list`(@TempDir tempDir: Path) = runTest {
+        val store = newDataStore(tempDir)
+        val prefs = SettingsPrefs(store)
+        // The pre-multi-reminder format stored a bare integer string.
+        store.updateData { p ->
+            val m = p.toMutablePreferences()
+            m[SettingsPrefs.DEFAULT_REMINDER_KEY] = "30"
+            m
+        }
+        assertThat(prefs.defaultReminderMinutes.first()).containsExactly(30)
+    }
+
+    @Test
+    fun `garbage stored default reminder reads as empty`(@TempDir tempDir: Path) = runTest {
         val store = newDataStore(tempDir)
         val prefs = SettingsPrefs(store)
         store.updateData { p ->
@@ -281,7 +297,7 @@ class SettingsPrefsTest {
             m[SettingsPrefs.DEFAULT_REMINDER_KEY] = "soon"
             m
         }
-        assertThat(prefs.defaultReminderMinutes.first()).isNull()
+        assertThat(prefs.defaultReminderMinutes.first()).isEmpty()
     }
 
     @Test
@@ -289,16 +305,16 @@ class SettingsPrefsTest {
         val prefs = SettingsPrefs(newDataStore(tempDir))
         assertThat(prefs.perCalendarReminderOverride.first()).isEmpty()
 
-        prefs.setCalendarReminderOverride(7L, CalendarReminderOverride.Minutes(15))
+        prefs.setCalendarReminderOverride(7L, CalendarReminderOverride.Minutes(listOf(15, 10_080)))
         prefs.setCalendarReminderOverride(9L, CalendarReminderOverride.None)
         prefs.perCalendarReminderOverride.first().let { map ->
-            assertThat(map).containsExactly(7L, 15, 9L, null)
+            assertThat(map).containsExactly(7L, listOf(15, 10_080), 9L, emptyList<Int>())
         }
 
-        // Inherit drops the override entirely (absent != null value).
+        // Inherit drops the override entirely (absent != an empty-list value).
         prefs.setCalendarReminderOverride(9L, CalendarReminderOverride.Inherit)
         prefs.perCalendarReminderOverride.first().let { map ->
-            assertThat(map).containsExactly(7L, 15)
+            assertThat(map).containsExactly(7L, listOf(15, 10_080))
             assertThat(map.containsKey(9L)).isFalse()
         }
     }
@@ -306,48 +322,48 @@ class SettingsPrefsTest {
     @Test
     fun `all-day default round-trips, including none`(@TempDir tempDir: Path) = runTest {
         val prefs = SettingsPrefs(newDataStore(tempDir))
-        assertThat(prefs.defaultAllDayReminderMinutes.first()).isNull()
-        prefs.setDefaultAllDayReminderMinutes(1_440)
-        assertThat(prefs.defaultAllDayReminderMinutes.first()).isEqualTo(1_440)
-        prefs.setDefaultAllDayReminderMinutes(null)
-        assertThat(prefs.defaultAllDayReminderMinutes.first()).isNull()
+        assertThat(prefs.defaultAllDayReminderMinutes.first()).isEmpty()
+        prefs.setDefaultAllDayReminderMinutes(listOf(1_440))
+        assertThat(prefs.defaultAllDayReminderMinutes.first()).containsExactly(1_440)
+        prefs.setDefaultAllDayReminderMinutes(emptyList())
+        assertThat(prefs.defaultAllDayReminderMinutes.first()).isEmpty()
     }
 
     @Test
     fun `per-calendar all-day override round-trips independently of the timed one`(@TempDir tempDir: Path) = runTest {
         val prefs = SettingsPrefs(newDataStore(tempDir))
-        prefs.setCalendarReminderOverride(7L, CalendarReminderOverride.Minutes(15))
-        prefs.setCalendarAllDayReminderOverride(7L, CalendarReminderOverride.Minutes(1_440))
-        assertThat(prefs.perCalendarReminderOverride.first()).containsExactly(7L, 15)
-        assertThat(prefs.perCalendarAllDayReminderOverride.first()).containsExactly(7L, 1_440)
+        prefs.setCalendarReminderOverride(7L, CalendarReminderOverride.Minutes(listOf(15)))
+        prefs.setCalendarAllDayReminderOverride(7L, CalendarReminderOverride.Minutes(listOf(1_440)))
+        assertThat(prefs.perCalendarReminderOverride.first()).containsExactly(7L, listOf(15))
+        assertThat(prefs.perCalendarAllDayReminderOverride.first()).containsExactly(7L, listOf(1_440))
         // Clearing the all-day override leaves the timed one untouched.
         prefs.setCalendarAllDayReminderOverride(7L, CalendarReminderOverride.Inherit)
         assertThat(prefs.perCalendarAllDayReminderOverride.first()).isEmpty()
-        assertThat(prefs.perCalendarReminderOverride.first()).containsExactly(7L, 15)
+        assertThat(prefs.perCalendarReminderOverride.first()).containsExactly(7L, listOf(15))
     }
 
     @Test
     fun `resolveDefaultReminder picks the kind-matching override or global`() {
-        val timed = mapOf(7L to 15, 9L to null)
-        val allDay = mapOf(7L to 2_880)
+        val timed = mapOf(7L to listOf(15, 10_080), 9L to emptyList<Int>())
+        val allDay = mapOf(7L to listOf(2_880))
         fun resolve(calendarId: Long?, isAllDay: Boolean) = resolveDefaultReminder(
-            timedGlobal = 30,
-            allDayGlobal = 1_440,
+            timedGlobal = listOf(30),
+            allDayGlobal = listOf(1_440),
             timedOverrides = timed,
             allDayOverrides = allDay,
             calendarId = calendarId,
             isAllDay = isAllDay,
         )
-        // Timed: minutes override, explicit none, inherit global, no calendar.
-        assertThat(resolve(7L, isAllDay = false)).isEqualTo(15)
-        assertThat(resolve(9L, isAllDay = false)).isNull()
-        assertThat(resolve(5L, isAllDay = false)).isEqualTo(30)
-        assertThat(resolve(null, isAllDay = false)).isEqualTo(30)
+        // Timed: multi-value override, explicit none, inherit global, no calendar.
+        assertThat(resolve(7L, isAllDay = false)).containsExactly(15, 10_080).inOrder()
+        assertThat(resolve(9L, isAllDay = false)).isEmpty()
+        assertThat(resolve(5L, isAllDay = false)).containsExactly(30)
+        assertThat(resolve(null, isAllDay = false)).containsExactly(30)
         // All-day: its own override wins; absent → all-day global; a timed-only
         // override (cal 9) does not bleed into all-day.
-        assertThat(resolve(7L, isAllDay = true)).isEqualTo(2_880)
-        assertThat(resolve(9L, isAllDay = true)).isEqualTo(1_440)
-        assertThat(resolve(5L, isAllDay = true)).isEqualTo(1_440)
+        assertThat(resolve(7L, isAllDay = true)).containsExactly(2_880)
+        assertThat(resolve(9L, isAllDay = true)).containsExactly(1_440)
+        assertThat(resolve(5L, isAllDay = true)).containsExactly(1_440)
     }
 
     @Test

app/src/test/java/de/jeanlucmakiola/calendula/data/reminders/PostableAlertsTest.kt

@@ -0,0 +1,55 @@
+package de.jeanlucmakiola.calendula.data.reminders
+
+import com.google.common.truth.Truth.assertThat
+import org.junit.jupiter.api.Test
+
+class PostableAlertsTest {
+
+    private fun alert(alertId: Long, calendarId: Long) = ReminderAlert(
+        alertId = alertId,
+        eventId = alertId * 10,
+        calendarId = calendarId,
+        beginMillis = 0L,
+        endMillis = 0L,
+        title = "Event $alertId",
+        location = null,
+        isAllDay = false,
+    )
+
+    @Test
+    fun `keeps alerts when no calendar is disabled`() {
+        val due = listOf(alert(1, calendarId = 100), alert(2, calendarId = 200))
+
+        val postable = postableAlerts(due, disabledCalendarIds = emptySet())
+
+        assertThat(postable).isEqualTo(due)
+    }
+
+    @Test
+    fun `drops alerts for a disabled calendar`() {
+        val keep = alert(1, calendarId = 100)
+        val drop = alert(2, calendarId = 200)
+
+        val postable = postableAlerts(listOf(keep, drop), disabledCalendarIds = setOf(200))
+
+        assertThat(postable).containsExactly(keep)
+    }
+
+    @Test
+    fun `drops every alert when all their calendars are disabled`() {
+        val due = listOf(alert(1, calendarId = 100), alert(2, calendarId = 100))
+
+        val postable = postableAlerts(due, disabledCalendarIds = setOf(100))
+
+        assertThat(postable).isEmpty()
+    }
+
+    @Test
+    fun `keeps multiple alerts from the same enabled calendar`() {
+        val due = listOf(alert(1, calendarId = 100), alert(2, calendarId = 100))
+
+        val postable = postableAlerts(due, disabledCalendarIds = setOf(999))
+
+        assertThat(postable).isEqualTo(due)
+    }
+}

app/src/test/java/de/jeanlucmakiola/calendula/domain/EventColorPaletteTest.kt

@@ -0,0 +1,214 @@
+package de.jeanlucmakiola.calendula.domain
+
+import com.google.common.truth.Truth.assertThat
+import org.junit.jupiter.api.Test
+
+class EventColorPaletteTest {
+
+    @Test
+    fun `empty palette stays empty`() {
+        assertThat(emptyList<EventColorOption>().curatedForPicker()).isEmpty()
+    }
+
+    @Test
+    fun `exact duplicate values collapse to the alphabetically first key`() {
+        val curated = listOf(
+            EventColorOption("cyan", 0xFF00FFFF.toInt()),
+            EventColorOption("aqua", 0xFF00FFFF.toInt()),
+            EventColorOption("red", 0xFFFF0000.toInt()),
+        ).curatedForPicker()
+
+        assertThat(curated.map { it.key }).containsExactly("aqua", "red")
+    }
+
+    @Test
+    fun `small palettes pass through whole, so Google's curated set is untouched`() {
+        // A Google-like palette: two dozen distinct hand-picked colours.
+        val palette = (0 until 24).map {
+            val hue = it * 15
+            EventColorOption("$it", hsvArgb(hue.toFloat()))
+        }
+
+        val curated = palette.curatedForPicker()
+
+        assertThat(curated).containsExactlyElementsIn(palette)
+    }
+
+    @Test
+    fun `oversized CSS3 palette thins to a pickable number of distinct swatches`() {
+        val curated = css3Palette().curatedForPicker()
+
+        // The whole point of #22: ~147 published colours become a single
+        // manageable grid instead of a full screen.
+        assertThat(curated.size).isAtLeast(30)
+        assertThat(curated.size).isAtMost(60)
+    }
+
+    @Test
+    fun `curation never invents colours or drops keys`() {
+        val source = css3Palette()
+        val curated = source.curatedForPicker()
+
+        assertThat(source).containsAtLeastElementsIn(curated)
+        assertThat(curated.map { it.argb }).containsNoDuplicates()
+    }
+
+    @Test
+    fun `spelling-alias pairs never both survive`() {
+        val keys = css3Palette().curatedForPicker().map { it.key }.toSet()
+
+        val aliasPairs = listOf(
+            "aqua" to "cyan",
+            "fuchsia" to "magenta",
+            "gray" to "grey",
+            "darkgray" to "darkgrey",
+            "dimgray" to "dimgrey",
+            "lightgray" to "lightgrey",
+            "slategray" to "slategrey",
+            "lightslategray" to "lightslategrey",
+            "darkslategray" to "darkslategrey",
+        )
+        aliasPairs.forEach { (a, b) ->
+            assertThat(keys.contains(a) && keys.contains(b)).isFalse()
+        }
+    }
+
+    @Test
+    fun `neutrals collapse to one painted tint instead of a run of look-alikes`() {
+        // Black and every gray paint as the same pale swatch (the picker pins
+        // lightness and floors saturation), so only one survives — no stranded
+        // run of look-alike "pinks" at the end of the grid (#22).
+        val curated = listOf(
+            EventColorOption("black", 0xFF000000.toInt()),
+            EventColorOption("gray", 0xFF808080.toInt()),
+            EventColorOption("darkgray", 0xFFA9A9A9.toInt()),
+            EventColorOption("blue", 0xFF0000FF.toInt()),
+            EventColorOption("red", 0xFFFF0000.toInt()),
+        ).curatedForPicker().map { it.key }
+
+        assertThat(curated).containsNoneOf("gray", "darkgray") // folded into black
+        assertThat(curated).containsAtLeast("black", "red", "blue")
+    }
+
+    @Test
+    fun `a dark and a light shade of one hue collapse to a single swatch`() {
+        // The picker paints every swatch at one fixed lightness, so navy and a
+        // mid blue are indistinguishable once painted — keep just one.
+        val curated = listOf(
+            EventColorOption("navy", 0xFF000080.toInt()),
+            EventColorOption("blue", 0xFF0000FF.toInt()),
+        ).curatedForPicker()
+
+        assertThat(curated).hasSize(1)
+    }
+
+    @Test
+    fun `the wheel is cut once, keeping each hue family contiguous`() {
+        // Twelve pure hues, deliberately shuffled; a small palette passes the
+        // thinning stage untouched so only the ordering is under test.
+        val shuffledHues = listOf(0, 300, 60, 180, 120, 240, 30, 330, 90, 210, 150, 270)
+        val curated = shuffledHues
+            .map { EventColorOption("$it", hsvArgb(it.toFloat())) }
+            .curatedForPicker()
+            .map { it.key.toInt() }
+
+        // A proper single-seam sweep around the wheel descends exactly once
+        // (at the seam). The old bucketed sort could scatter a family across
+        // both ends, producing extra descents.
+        val descents = curated.indices.count { i ->
+            curated[(i + 1) % curated.size] < curated[i]
+        }
+        assertThat(descents).isEqualTo(1)
+    }
+
+    @Test
+    fun `CSS3 survivors span the whole rainbow`() {
+        val keys = css3Palette().curatedForPicker().map { it.key }
+        fun has(vararg families: String) = keys.any { k -> families.any { k.contains(it) } }
+
+        // Which exact name represents a hue family depends on the vivid-first
+        // thinning, so assert each family survives, not a specific key.
+        assertThat(has("red", "crimson", "firebrick", "tomato", "maroon", "brown")).isTrue()
+        assertThat(has("orange", "gold", "goldenrod", "peru", "sienna", "salmon")).isTrue()
+        assertThat(has("green", "olive", "lime", "chartreuse", "forest", "sea")).isTrue()
+        assertThat(has("blue", "navy", "dodger", "steel", "royal", "sky", "aqua")).isTrue()
+        assertThat(has("violet", "purple", "magenta", "orchid", "fuchsia", "indigo", "plum")).isTrue()
+    }
+
+    private fun hsvArgb(hue: Float): Int {
+        val h = hue / 60f
+        val sector = h.toInt() % 6
+        val f = h - h.toInt()
+        val q = ((1 - f) * 255).toInt()
+        val t = (f * 255).toInt()
+        return when (sector) {
+            0 -> argb(255, t, 0)
+            1 -> argb(q, 255, 0)
+            2 -> argb(0, 255, t)
+            3 -> argb(0, q, 255)
+            4 -> argb(t, 0, 255)
+            else -> argb(255, 0, q)
+        }
+    }
+
+    private fun argb(r: Int, g: Int, b: Int): Int =
+        (0xFF shl 24) or (r shl 16) or (g shl 8) or b
+
+    /** The exact set ical4android/DAVx5 publishes: CSS3's 147 named colours. */
+    private fun css3Palette(): List<EventColorOption> = CSS3.map { (name, rgb) ->
+        EventColorOption(name, 0xFF000000.toInt() or rgb)
+    }
+
+    private val CSS3 = mapOf(
+        "aliceblue" to 0xF0F8FF, "antiquewhite" to 0xFAEBD7, "aqua" to 0x00FFFF,
+        "aquamarine" to 0x7FFFD4, "azure" to 0xF0FFFF, "beige" to 0xF5F5DC,
+        "bisque" to 0xFFE4C4, "black" to 0x000000, "blanchedalmond" to 0xFFEBCD,
+        "blue" to 0x0000FF, "blueviolet" to 0x8A2BE2, "brown" to 0xA52A2A,
+        "burlywood" to 0xDEB887, "cadetblue" to 0x5F9EA0, "chartreuse" to 0x7FFF00,
+        "chocolate" to 0xD2691E, "coral" to 0xFF7F50, "cornflowerblue" to 0x6495ED,
+        "cornsilk" to 0xFFF8DC, "crimson" to 0xDC143C, "cyan" to 0x00FFFF,
+        "darkblue" to 0x00008B, "darkcyan" to 0x008B8B, "darkgoldenrod" to 0xB8860B,
+        "darkgray" to 0xA9A9A9, "darkgreen" to 0x006400, "darkgrey" to 0xA9A9A9,
+        "darkkhaki" to 0xBDB76B, "darkmagenta" to 0x8B008B, "darkolivegreen" to 0x556B2F,
+        "darkorange" to 0xFF8C00, "darkorchid" to 0x9932CC, "darkred" to 0x8B0000,
+        "darksalmon" to 0xE9967A, "darkseagreen" to 0x8FBC8F, "darkslateblue" to 0x483D8B,
+        "darkslategray" to 0x2F4F4F, "darkslategrey" to 0x2F4F4F, "darkturquoise" to 0x00CED1,
+        "darkviolet" to 0x9400D3, "deeppink" to 0xFF1493, "deepskyblue" to 0x00BFFF,
+        "dimgray" to 0x696969, "dimgrey" to 0x696969, "dodgerblue" to 0x1E90FF,
+        "firebrick" to 0xB22222, "floralwhite" to 0xFFFAF0, "forestgreen" to 0x228B22,
+        "fuchsia" to 0xFF00FF, "gainsboro" to 0xDCDCDC, "ghostwhite" to 0xF8F8FF,
+        "gold" to 0xFFD700, "goldenrod" to 0xDAA520, "gray" to 0x808080,
+        "green" to 0x008000, "greenyellow" to 0xADFF2F, "grey" to 0x808080,
+        "honeydew" to 0xF0FFF0, "hotpink" to 0xFF69B4, "indianred" to 0xCD5C5C,
+        "indigo" to 0x4B0082, "ivory" to 0xFFFFF0, "khaki" to 0xF0E68C,
+        "lavender" to 0xE6E6FA, "lavenderblush" to 0xFFF0F5, "lawngreen" to 0x7CFC00,
+        "lemonchiffon" to 0xFFFACD, "lightblue" to 0xADD8E6, "lightcoral" to 0xF08080,
+        "lightcyan" to 0xE0FFFF, "lightgoldenrodyellow" to 0xFAFAD2, "lightgray" to 0xD3D3D3,
+        "lightgreen" to 0x90EE90, "lightgrey" to 0xD3D3D3, "lightpink" to 0xFFB6C1,
+        "lightsalmon" to 0xFFA07A, "lightseagreen" to 0x20B2AA, "lightskyblue" to 0x87CEFA,
+        "lightslategray" to 0x778899, "lightslategrey" to 0x778899, "lightsteelblue" to 0xB0C4DE,
+        "lightyellow" to 0xFFFFE0, "lime" to 0x00FF00, "limegreen" to 0x32CD32,
+        "linen" to 0xFAF0E6, "magenta" to 0xFF00FF, "maroon" to 0x800000,
+        "mediumaquamarine" to 0x66CDAA, "mediumblue" to 0x0000CD, "mediumorchid" to 0xBA55D3,
+        "mediumpurple" to 0x9370DB, "mediumseagreen" to 0x3CB371, "mediumslateblue" to 0x7B68EE,
+        "mediumspringgreen" to 0x00FA9A, "mediumturquoise" to 0x48D1CC,
+        "mediumvioletred" to 0xC71585, "midnightblue" to 0x191970, "mintcream" to 0xF5FFFA,
+        "mistyrose" to 0xFFE4E1, "moccasin" to 0xFFE4B5, "navajowhite" to 0xFFDEAD,
+        "navy" to 0x000080, "oldlace" to 0xFDF5E6, "olive" to 0x808000,
+        "olivedrab" to 0x6B8E23, "orange" to 0xFFA500, "orangered" to 0xFF4500,
+        "orchid" to 0xDA70D6, "palegoldenrod" to 0xEEE8AA, "palegreen" to 0x98FB98,
+        "paleturquoise" to 0xAFEEEE, "palevioletred" to 0xDB7093, "papayawhip" to 0xFFEFD5,
+        "peachpuff" to 0xFFDAB9, "peru" to 0xCD853F, "pink" to 0xFFC0CB,
+        "plum" to 0xDDA0DD, "powderblue" to 0xB0E0E6, "purple" to 0x800080,
+        "red" to 0xFF0000, "rosybrown" to 0xBC8F8F, "royalblue" to 0x4169E1,
+        "saddlebrown" to 0x8B4513, "salmon" to 0xFA8072, "sandybrown" to 0xF4A460,
+        "seagreen" to 0x2E8B57, "seashell" to 0xFFF5EE, "sienna" to 0xA0522D,
+        "silver" to 0xC0C0C0, "skyblue" to 0x87CEEB, "slateblue" to 0x6A5ACD,
+        "slategray" to 0x708090, "slategrey" to 0x708090, "snow" to 0xFFFAFA,
+        "springgreen" to 0x00FF7F, "steelblue" to 0x4682B4, "tan" to 0xD2B48C,
+        "teal" to 0x008080, "thistle" to 0xD8BFD8, "tomato" to 0xFF6347,
+        "turquoise" to 0x40E0D0, "violet" to 0xEE82EE, "wheat" to 0xF5DEB3,
+        "white" to 0xFFFFFF, "whitesmoke" to 0xF5F5F5, "yellow" to 0xFFFF00,
+        "yellowgreen" to 0x9ACD32,
+    )
+}