diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/SessionScreen.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/SessionScreen.kt
index 27fce6a..5b6b9fe 100644
--- a/app/androidApp/src/main/kotlin/com/example/aiapp/SessionScreen.kt
+++ b/app/androidApp/src/main/kotlin/com/example/aiapp/SessionScreen.kt
@@ -8,7 +8,6 @@ import androidx.activity.result.PickVisualMediaRequest
 import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.foundation.Image
 import androidx.compose.foundation.layout.Box
-import androidx.compose.foundation.layout.BoxWithConstraints
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
@@ -1415,13 +1414,10 @@ fun SessionScreen(settings: ServerSettings, summary: SessionSummary, onBack: ()
         // is no frame in which the transcript is somewhere other than where it was left.
         val settled = !restoring && !listState.settling
         Box(Modifier.weight(1f).fillMaxWidth()) {
-            BoxWithConstraints(Modifier.fillMaxSize()) {
+            Box(Modifier.fillMaxSize()) {
                 TranscriptColumn(
                     rows = rows,
                     state = listState,
-                    // A scrollable child is measured with no height bound, so the content cannot
-                    // ask how tall the visible area is; this is the only place that knows.
-                    viewportHeight = maxHeight,
                     contentPadding = TRANSCRIPT_PADDING,
                     spacing = TRANSCRIPT_SPACING,
                     modifier =
diff --git a/app/androidApp/src/main/kotlin/com/example/aiapp/TranscriptScroll.kt b/app/androidApp/src/main/kotlin/com/example/aiapp/TranscriptScroll.kt
index 1a8d88c..779d33c 100644
--- a/app/androidApp/src/main/kotlin/com/example/aiapp/TranscriptScroll.kt
+++ b/app/androidApp/src/main/kotlin/com/example/aiapp/TranscriptScroll.kt
@@ -9,7 +9,6 @@ import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
-import androidx.compose.foundation.layout.heightIn
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.verticalScroll
@@ -18,6 +17,7 @@ import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.Stable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.key
+import androidx.compose.runtime.mutableIntStateOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
@@ -28,6 +28,7 @@ import androidx.compose.ui.draw.drawWithContent
 import androidx.compose.ui.graphics.graphicsLayer
 import androidx.compose.ui.input.pointer.PointerEventPass
 import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.ui.layout.layout
 import androidx.compose.ui.layout.onPlaced
 import androidx.compose.ui.layout.onSizeChanged
 import androidx.compose.ui.platform.LocalDensity
@@ -89,8 +90,13 @@ class TranscriptScroll(internal val scroll: ScrollState) {
     private var rowIndex = HashMap<Long, Int>()
     private var topsStale = true
 
+    /** How many rows the list is drawing, so the window notices one arriving. */
+    var rowCount: Int by mutableIntStateOf(0)
+        private set
+
     internal fun laidOut(order: List<Long>, spacing: Int, padTop: Int) {
         this.order = order
+        rowCount = order.size
         this.spacing = spacing
         this.padTop = padTop
         rowIndex = HashMap(order.size)
@@ -286,10 +292,16 @@ class TranscriptScroll(internal val scroll: ScrollState) {
      * either side and this moves it in steps of two, so the margin absorbs the staleness.
      */
     internal fun trackRetained() {
+        // Before the comparison, not after it. Rows arriving is the case this exists to catch and
+        // it does not move the view: a message sent lands at the newest end, and if the range is
+        // not recomputed the new row is outside it and stands in as a spacer of its guessed height
+        // -- a screen of blank between the last message and the box it was typed in. The version
+        // it is compared against is only bumped by this call, so asking first meant never noticing.
+        refreshTops()
         val viewportTop = scroll.maxValue - scroll.value
         val step = (scroll.viewportSize * RETAIN_STEP_SCREENS).coerceAtLeast(1)
         val moved = viewportTop - rangeAt
-        if (retained.isEmpty() || moved > step || moved < -step || topsVersion != rangeVersion) {
+        if (retained.isEmpty() || topsVersion != rangeVersion || moved > step || moved < -step) {
             retained = retainedRange(viewportTop)
         }
     }
@@ -410,7 +422,6 @@ fun rememberTranscriptScroll(key: Any?): TranscriptScroll {
 fun TranscriptColumn(
     rows: List<TranscriptRow>,
     state: TranscriptScroll,
-    viewportHeight: Dp,
     contentPadding: PaddingValues,
     spacing: Dp,
     modifier: Modifier = Modifier,
@@ -438,7 +449,20 @@ fun TranscriptColumn(
         modifier
             .verticalScroll(state.scroll, reverseScrolling = true)
             .padding(contentPadding)
-            .heightIn(min = viewportHeight)
+            // As tall as the visible area at least, so a conversation shorter than the screen sits
+            // against the composer rather than leaving a gap under it that cannot be scrolled away.
+            //
+            // Taken in the layout phase from the scroll container's own measurement, rather than
+            // from a `BoxWithConstraints` around this. That is a `SubcomposeLayout`, and the
+            // keyboard opening changes the visible height on every frame of its animation -- so
+            // the whole transcript was being subcomposed again for each of those frames, which is
+            // what made bringing the keyboard up cost more than anything else on the screen. Read
+            // here it is a relayout, and the rows keep the measurements they already have.
+            .layout { measurable, constraints ->
+                val placeable =
+                    measurable.measure(constraints.copy(minHeight = state.scroll.viewportSize))
+                layout(placeable.width, placeable.height) { placeable.place(0, 0) }
+            }
             .fillMaxWidth()
             // Once for the whole list, not once per row: this is where a saved position is put
             // back, and by placement the scroll container's own measurements describe this layout.