feat(widget): open the app from the widget headers (#18, #20)

Tapping a widget header now opens the app on a sensible top-level view,
via a shared WidgetNavRequest.OpenView(view?) — a concrete view roots
there over the default home, a null view resolves to the default home:

- Month widget: the month/year title opens the month view (#18). Its
  "today" button now snaps the grid back to the current month in place
  (the reset that used to sit on the title), so paging + jump-to-today
  are both reachable and the title is free to open the app.
- Agenda widget: the "Upcoming" title opens the default view (#20), so
  users whose home view is Week/Month can reach it in one tap instead of
  drilling through a day or event.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -5,6 +5,39 @@ 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. The month widget's "today" button now snaps the grid back to the
+  current month in place. Thanks to @rgz46vic and @ptab for the suggestions
+  ([#18], [#20]).
+
+### Fixed
+- 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 +762,8 @@ 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

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/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

@@ -276,35 +276,36 @@ 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() }
     }
 
     /**
@@ -341,13 +342,13 @@ 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])
     }
 
@@ -364,7 +365,7 @@ 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])
     }
 
@@ -495,43 +496,46 @@ 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())
     }
 }
 
@@ -557,24 +561,36 @@ 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/ui/CalendarHost.kt

@@ -212,6 +212,17 @@ 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/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/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

@@ -969,7 +969,7 @@ 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 },
         )
     }
@@ -979,7 +979,7 @@ 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 },
         )
     }
@@ -1028,13 +1028,13 @@ 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
@@ -1109,27 +1109,33 @@ 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

@@ -44,24 +44,24 @@ 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

@@ -139,15 +139,15 @@ 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>,
     )
 
@@ -255,11 +255,11 @@ 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,

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

@@ -316,7 +316,6 @@
     <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

@@ -324,7 +324,6 @@
     <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

@@ -183,22 +183,38 @@ 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 ->
@@ -206,7 +222,7 @@ class SettingsPrefsTest {
             m[SettingsPrefs.DEFAULT_REMINDER_KEY] = "soon"
             m
         }
-        assertThat(prefs.defaultReminderMinutes.first()).isNull()
+        assertThat(prefs.defaultReminderMinutes.first()).isEmpty()
     }
 
     @Test
@@ -214,16 +230,16 @@ 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()
         }
     }
@@ -231,48 +247,48 @@ 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)
+    }
+}