app/src/main/java/de/jeanlucmakiola/calendula/ui/month/MonthMorph.kt

@@ -66,6 +66,25 @@ internal class MonthMorphScope(
 
 internal val LocalMonthMorph = compositionLocalOf<MonthMorphScope?> { null }
 
+/**
+ * True while the grid is mid-morph, for content that has to stop clipping to let
+ * the travelling pieces through.
+ *
+ * A mark's two homes are in *different rows*: the dot for the 20th sits a third
+ * of the way down the compact grid, its bar most of the way down the expanded
+ * one. Clipped to the row it is arriving at, a mark spends the first half of its
+ * journey outside those bounds and is simply not drawn — so it appears from
+ * nowhere, part-way through, already near its destination. Rendering in place
+ * rather than in an overlay is what subjects them to that clip, and is worth
+ * keeping; the clip is what has to yield, and only while pieces are in flight.
+ */
+@OptIn(ExperimentalSharedTransitionApi::class)
+@Composable
+internal fun morphInFlight(): Boolean {
+    val morph = LocalMonthMorph.current ?: return false
+    return morph.shared.isTransitionActive
+}
+
 /**
  * Tag content that is *the same thing* on both sides — a background pill, a day
  * number — so it animates between its two positions and sizes.

app/src/main/java/de/jeanlucmakiola/calendula/ui/month/MonthScreen.kt

@@ -1647,6 +1647,7 @@ private fun MonthWeekRow(
     val dark = isSystemInDarkTheme()
     val laneCount = (week.spans.maxOfOrNull { it.lane } ?: -1) + 1
     val shownLanes = laneCount.coerceAtMost(MAX_EVENT_ROWS)
+    val morphing = morphInFlight()
 
     Row(modifier) {
         // Optional calendar-week gutter, sized so the seven day columns below
@@ -1720,11 +1721,15 @@ private fun MonthWeekRow(
                 // Breathing room between the day number (and today's circle) and the
                 // first event row.
                 Spacer(Modifier.height(DAY_NUMBER_GAP))
+                // Clipped at rest so a bar can't spill into the row below, but not
+                // while a morph is in flight: a mark travels between two different
+                // rows, and clipping it to the one it is arriving at hides it for
+                // the whole first half of the journey. See [morphInFlight].
                 Box(
                     modifier = Modifier
                         .fillMaxWidth()
                         .weight(1f)
-                        .clipToBounds(),
+                        .then(if (morphing) Modifier else Modifier.clipToBounds()),
                 ) {
                     // Spanning bars on their shared lanes.
                     week.spans.filter { it.lane < shownLanes }.forEach { span ->