build: bump to 4.4.7-ba7opf.13

Tapping the grid-QSO dialog "Match" button now starts the pass query on
the map page and only navigates to the match page once it finishes, so the
page's first frame already contains the results — the time-range card at
the top and the pass curves right below, with no scroll flicker. The dialog
button shows a spinner and is disabled while calculating. A uiState
collector in MainScreen performs the actual navigation (still a push, so
the back gesture returns to the map). Failures/exceptions still navigate so
the user is never stuck on the map page.

app/src/main/java/com/rtbishop/look4sat/MainScreen.kt

@@ -177,6 +177,28 @@ fun MainScreen(
         factory = MapFilterViewModel.factory()
     )
 
+    // Map grid-QSO dialog "Match" button: pre-fill the match page for that
+    // grid and run the query BEFORE navigating, so the page's first frame
+    // already contains the results (time-range card at the top, pass curves
+    // right below — no scroll flicker). Navigation happens once the query
+    // finishes (see the collector below).
+    val mutualState by mutualViewModel.uiState.collectAsStateWithLifecycle()
+    val matchCalculating = mutualState.pendingNavigation && mutualState.isCalculating
+
+    LaunchedEffect(mutualViewModel) {
+        mutualViewModel.uiState.collect { state ->
+            if (state.pendingNavigation && !state.isCalculating) {
+                mutualViewModel.consumePendingNavigation()
+                // Push Mutual on top of the Map entry instead of replacing the
+                // stack (bottom-nav style): the system back gesture then pops
+                // back to the map page, which is the page the user came from.
+                if (backStack.lastOrNull() !is Screen.Mutual) {
+                    backStack.add(Screen.Mutual)
+                }
+            }
+        }
+    }
+
     CompositionLocalProvider(
         LocalElevationThresholds provides ElevationThresholds(
             low = otherSettings.lowElevation,
@@ -246,12 +268,14 @@ fun MainScreen(
                         entry<Screen.Map> {
                             MapDestination(
                                 mapFilterViewModel = mapFilterViewModel,
+                                matchCalculating = matchCalculating,
                                 onMatchGrid = { grid ->
-                                    // Grid-QSO dialog "Match" button: pre-fill the
+                                    // Grid-QSO dialog "Match" button: pre-fill
-                                    // match page for that grid and switch to its tab.
+                                    // the match page for that grid and start the
+                                    // query. Navigation to the match page is
+                                    // handled by the uiState collector above,
+                                    // once the query finishes.
                                     mutualViewModel.prefillMatchFromGrid(grid)
-                                    while (backStack.size > 1) backStack.removeAt(backStack.size - 1)
-                                    backStack.add(Screen.Mutual)
                                 }
                             )
                         }

feature/map/src/main/java/com/rtbishop/look4sat/feature/map/MapScreen.kt

@@ -54,6 +54,7 @@ import androidx.compose.material3.Surface
 import androidx.compose.material3.Switch
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
+import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.LaunchedEffect
@@ -153,7 +154,10 @@ fun MapDestination(
     mapFilterViewModel: MapFilterViewModel,
     // Invoked with the tapped grid when the QSO dialog's "Match" button is
     // pressed: navigate to the match page pre-filled for that grid.
-    onMatchGrid: (String) -> Unit = {}
+    onMatchGrid: (String) -> Unit = {},
+    // True while the map "Match" query is running (the page only navigates
+    // once the query finished, so the match page opens with results ready).
+    matchCalculating: Boolean = false
 ) {
     val context = LocalContext.current
     val container = (context.applicationContext as IContainerProvider).getMainContainer()
@@ -190,7 +194,7 @@ fun MapDestination(
             viewModel.onAction(MapAction.SetVisible(false))
         }
     }
-    MapScreen(uiState, viewModel::onAction, mapView, mapFilterViewModel, onMatchGrid)
+    MapScreen(uiState, viewModel::onAction, mapView, mapFilterViewModel, onMatchGrid, matchCalculating)
 }
 
 @Composable
@@ -199,7 +203,8 @@ private fun MapScreen(
     onAction: (MapAction) -> Unit,
     mapView: MapView,
     mapFilterViewModel: MapFilterViewModel,
-    onMatchGrid: (String) -> Unit
+    onMatchGrid: (String) -> Unit,
+    matchCalculating: Boolean
 ) {
     val rotateMod = Modifier.rotate(180f)
     val timeString = uiState.mapData?.aosTime ?: "00:00:00"
@@ -423,6 +428,7 @@ private fun MapScreen(
             grid = grid,
             qsos = uiState.workedGridQsos[grid].orEmpty().sortedBy { it.epochMs },
             isUtc = uiState.isUtc,
+            matchCalculating = matchCalculating,
             onDismiss = { selectedGrid = null },
             onMatch = { onMatchGrid(grid) }
         )
@@ -436,6 +442,7 @@ private fun WorkedGridQsoDialog(
     grid: String,
     qsos: List<com.rtbishop.look4sat.core.domain.model.GridQso>,
     isUtc: Boolean,
+    matchCalculating: Boolean,
     onDismiss: () -> Unit,
     onMatch: () -> Unit
 ) {
@@ -467,16 +474,24 @@ private fun WorkedGridQsoDialog(
                         )
                     }
                     TextButton(
+                        enabled = !matchCalculating,
                         onClick = {
                             onDismiss()
                             onMatch()
                         }
                     ) {
-                        Icon(
+                        if (matchCalculating) {
-                            painter = painterResource(R.drawable.ic_radio_tower),
+                            CircularProgressIndicator(
-                            contentDescription = null,
+                                modifier = Modifier.size(18.dp),
-                            modifier = Modifier.size(18.dp)
+                                strokeWidth = 2.dp
-                        )
+                            )
+                        } else {
+                            Icon(
+                                painter = painterResource(R.drawable.ic_radio_tower),
+                                contentDescription = null,
+                                modifier = Modifier.size(18.dp)
+                            )
+                        }
                         Spacer(Modifier.width(4.dp))
                         Text(stringResource(R.string.grid_qso_match))
                     }

feature/mutual/build.gradle.kts

@@ -18,5 +18,6 @@ dependencies {
     testImplementation(libs.robolectric)
     testImplementation(libs.androidx.test.core)
     testImplementation(libs.compose.ui.test.junit4)
+    testImplementation(libs.compose.navigation3)
     debugImplementation(libs.compose.debug.manifest)
 }

feature/mutual/src/main/java/com/rtbishop/look4sat/feature/mutual/MutualScreen.kt

@@ -17,6 +17,7 @@
  */
 package com.rtbishop.look4sat.feature.mutual
 
+import android.util.Log
 import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.animation.expandVertically
 import androidx.compose.animation.shrinkVertically
@@ -54,11 +55,13 @@ import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableFloatStateOf
+import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.runtime.snapshotFlow
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.layout.onGloballyPositioned
 import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.font.FontWeight
@@ -77,6 +80,7 @@ import java.text.SimpleDateFormat
 import java.util.Date
 import java.util.Locale
 import java.util.TimeZone
+import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.distinctUntilChanged
 
 @Composable
@@ -157,7 +161,7 @@ fun MutualScreen(
             viewModel = viewModel,
             state = state,
             isVertical = isVertical,
-            onQuery = viewModel::queryMutualPasses,
+            onQuery = { viewModel.queryMutualPasses() },
             onSelectPass = viewModel::onSelectPass,
             onNavigateToRadar = navigateToRadar,
             onStationALat = viewModel::onStationALat,
@@ -220,8 +224,24 @@ private fun MutualContent(
             }
     }
 
+    // Set once the list has actually been laid out. The prefill scroll only
+    // fires after this, because on a real device the Mutual entry appears
+    // through the NavDisplay transition and LaunchedEffect alone can run
+    // before the list is measurable (the scroll then never lands and the
+    // page stays at the top). onGloballyPositioned fires on the first real
+    // layout, so the subsequent scrollToItem always has a measured list.
+    var listReady by remember { mutableStateOf(false) }
+    Log.d(TAG, "composed: scrollToTimeRange=${state.scrollToTimeRange} matchIndex=${if (state.errorMessage != null) 2 else 1} listReady=$listReady")
+
     LazyColumn(
-        modifier = Modifier.fillMaxSize(),
+        modifier = Modifier
+            .fillMaxSize()
+            .onGloballyPositioned {
+                if (!listReady) {
+                    Log.d(TAG, "lazy list laid out, opening prefill scroll gate")
+                    listReady = true
+                }
+            },
         state = listState,
         verticalArrangement = Arrangement.spacedBy(6.dp)
     ) {
@@ -377,14 +397,36 @@ private fun MutualContent(
     // LazyListState at index 1: the constructor parameter is ignored by this
     // Compose version (verified in tests), while scrollToItem lands correctly.
     val matchSearchIndex = if (state.errorMessage != null) 2 else 1
-    LaunchedEffect(state.scrollToTimeRange, matchSearchIndex) {
+    LaunchedEffect(state.scrollToTimeRange, matchSearchIndex, listReady) {
-        if (state.scrollToTimeRange) {
+        Log.d(TAG, "scroll effect: scrollToTimeRange=${state.scrollToTimeRange} matchIndex=$matchSearchIndex listReady=$listReady")
-            listState.scrollToItem(matchSearchIndex)
+        if (state.scrollToTimeRange && listReady) {
+            // Keep trying until the scroll really lands: on a device the first
+            // frame only contains the station cards + time-range card, which
+            // can be shorter than the viewport (no scroll range), so a single
+            // scrollToItem does nothing. When the async query results arrive
+            // the list grows past one screen and the scroll becomes possible.
+            for (attempt in 0 until 20) {
+                Log.d(TAG, "attempting scrollToItem($matchSearchIndex) #$attempt")
+                try {
+                    listState.scrollToItem(matchSearchIndex)
+                } catch (t: Throwable) {
+                    Log.e(TAG, "scrollToItem($matchSearchIndex) threw", t)
+                    break
+                }
+                if (listState.firstVisibleItemIndex == matchSearchIndex) {
+                    Log.d(TAG, "scroll landed at $matchSearchIndex on attempt #$attempt")
+                    break
+                }
+                delay(100)
+            }
             viewModel.consumeScrollToTimeRange()
+            Log.d(TAG, "scrollToTimeRange consumed")
         }
     }
 }
 
+private const val TAG = "Look4SatMutual"
+
 @Composable
 private fun MutualStatusChip(state: MutualUiState) {
     val colorScheme = MaterialTheme.colorScheme

feature/mutual/src/main/java/com/rtbishop/look4sat/feature/mutual/MutualViewModel.kt

@@ -40,6 +40,8 @@ import kotlinx.coroutines.withContext
 import kotlin.math.PI
 import kotlin.math.roundToInt
 
+private const val TAG = "Look4SatMutual"
+
 data class MutualUiState(
     val stationALat: String = "",
     val stationALon: String = "",
@@ -59,7 +61,12 @@ data class MutualUiState(
     // One-shot flag set by prefillMatchFromGrid() (map grid → Match button):
     // the page scrolls to the time-range card after the first layout, then
     // consumeScrollToTimeRange() clears it.
-    val scrollToTimeRange: Boolean = false
+    val scrollToTimeRange: Boolean = false,
+    // One-shot flag set by prefillMatchFromGrid(): the map page waits for the
+    // pre-filled query to finish, then navigates to the match page so the very
+    // first frame already contains the results (time-range card + pass curves,
+    // no scroll flicker). consumePendingNavigation() clears it.
+    val pendingNavigation: Boolean = false
 )
 
 class MutualViewModel(
@@ -197,23 +204,40 @@ class MutualViewModel(
     fun prefillMatchFromGrid(grid: String) {
         val g = grid.trim().uppercase()
         val pos = qthToPosition(g)
+        android.util.Log.d(TAG, "prefillMatchFromGrid('$g')")
         _uiState.update {
             it.copy(
                 stationBGrid = g,
                 stationBLat = pos?.let { p -> "%.4f".format(p.latitude) } ?: it.stationBLat,
                 stationBLon = pos?.let { p -> "%.4f".format(p.longitude) } ?: it.stationBLon,
                 hoursAhead = 24,
-                scrollToTimeRange = true
+                scrollToTimeRange = true,
+                pendingNavigation = true
             )
         }
         queryMutualPasses()
     }
 
+    fun consumePendingNavigation() {
+        android.util.Log.d(TAG, "consumePendingNavigation")
+        _uiState.update { it.copy(pendingNavigation = false) }
+    }
+
     fun consumeScrollToTimeRange() {
+        android.util.Log.d(TAG, "consumeScrollToTimeRange")
         _uiState.update { it.copy(scrollToTimeRange = false) }
     }
 
-    fun queryMutualPasses(initialScrollIndex: Int = 0) {
+    /**
+     * Run a mutual-pass query. `initialScrollIndex` non-null forces the list
+     * to rebuild at that position (legacy callers); null keeps the current
+     * scroll position, so re-running a query from the match page does not
+     * jump back to the top. The previous results stay on screen while the
+     * query runs (the list keeps its height, so the scroll position is not
+     * clamped away); they are replaced — possibly with empty — when the new
+     * results arrive.
+     */
+    fun queryMutualPasses(initialScrollIndex: Int? = null) {
         val state = _uiState.value
 
         // Resolve positions from lat/lon or grid
@@ -236,16 +260,19 @@ class MutualViewModel(
                 isCalculating = true,
                 hasSearched = true,
                 errorMessage = null,
-                mutualPasses = emptyList(),
+                // Deliberately keep mutualPasses: clearing it would shrink the
+                // list below one screen and clamp the scroll position away.
+                // The stale results are replaced when the new ones arrive.
                 selectedPassIndex = -1
             )
         }
-        // The results list is about to be replaced, so the scroll position must
+        // Scroll position: an explicit initialScrollIndex overrides (legacy
-        // not leak from the previous query's list. A prefill from the map
+        // callers start at a fixed spot); null keeps the current position so
-        // (grid-QSO dialog "Match" button) instead starts at the time-range
+        // re-querying does not jump back to the top.
-        // card so the page opens with it at the top.
+        if (initialScrollIndex != null) {
-        listScrollIndex = initialScrollIndex
+            listScrollIndex = initialScrollIndex
-        listScrollOffset = 0
+            listScrollOffset = 0
+        }
         queryGeneration += 1
 
         viewModelScope.launch {
@@ -254,8 +281,15 @@ class MutualViewModel(
             val minElevB = state.stationBMinElev
             val hours = state.hoursAhead
 
-            val results = withContext(computeDispatcher) {
+            val results = try {
-                findMutualPasses(satellites, posA, posB, minElevA, minElevB, time, hours)
+                withContext(computeDispatcher) {
+                    findMutualPasses(satellites, posA, posB, minElevA, minElevB, time, hours)
+                }
+            } catch (t: Throwable) {
+                // Never leave the query stuck in "calculating" (which would also
+                // block the pending map→match navigation forever).
+                android.util.Log.e(TAG, "findMutualPasses threw", t)
+                emptyList()
             }
 
             val errorMsg = if (results.isEmpty()) {

feature/mutual/src/test/java/com/rtbishop/look4sat/feature/mutual/MutualMatchPrefillScrollTest.kt

@@ -1,6 +1,8 @@
 package com.rtbishop.look4sat.feature.mutual
 
+import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.LazyListState
 import androidx.compose.material3.MaterialTheme
@@ -8,10 +10,19 @@ import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.mutableStateOf
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.test.assertIsDisplayed
+import androidx.compose.ui.unit.dp
 import androidx.compose.ui.test.junit4.createComposeRule
 import androidx.compose.ui.test.onNodeWithText
+import androidx.navigation3.runtime.NavBackStack
+import androidx.navigation3.runtime.NavKey
+import androidx.navigation3.runtime.entryProvider
+import androidx.navigation3.runtime.rememberNavBackStack
+import androidx.navigation3.ui.NavDisplay
+import com.rtbishop.look4sat.core.presentation.Screen
+import kotlinx.coroutines.delay
 import org.junit.Assert.assertTrue
 import org.junit.Rule
 import org.junit.Test
@@ -38,7 +49,7 @@ import org.robolectric.annotation.GraphicsMode
  */
 @RunWith(RobolectricTestRunner::class)
 @GraphicsMode(GraphicsMode.Mode.NATIVE)
-@Config(sdk = [34])
+@Config(sdk = [34], qualifiers = "w411dp-h891dp-port")
 class MutualMatchPrefillScrollTest {
 
     @get:Rule
@@ -108,6 +119,15 @@ class MutualMatchPrefillScrollTest {
         // The time-range card must be visible at the top of the page after the
         // prefill scroll.
         composeRule.onNodeWithText("Time range").assertIsDisplayed()
+        // The snapshotFlow write-back stores the scrolled position in the VM.
+        // It equals 1 only if scrollToItem(1) REALLY scrolled the station card
+        // out. If the list content is shorter than the viewport there is no
+        // scroll range, scrollToItem cannot move, and this stays 0 — that is
+        // exactly the device symptom ("page stays at the top").
+        org.junit.Assert.assertEquals(
+            "list must have actually scrolled to item 1 (content shorter than viewport?)",
+            1, vm.listScrollIndex
+        )
     }
 
     @Test
@@ -126,5 +146,146 @@ class MutualMatchPrefillScrollTest {
         // ...and the target grid + 24h range pre-filled.
         org.junit.Assert.assertEquals("OL62", s.stationBGrid)
         org.junit.Assert.assertEquals(24, s.hoursAhead)
+        // ...and navigation to the match page is pending until the query done.
+        assertTrue("navigation should be pending", s.pendingNavigation)
+        // The early-return guard means the query finished immediately (no
+        // satellites): the map page must now be free to navigate.
+        org.junit.Assert.assertFalse("query finished -> not calculating", s.isCalculating)
+        vm.consumePendingNavigation()
+        org.junit.Assert.assertFalse("consume clears pending navigation", vm.uiState.value.pendingNavigation)
+    }
+
+    @Test
+    fun navDisplayEntryAfterPrefill_scrollsToTimeRange() {
+        // The Mutual screen composed inside a NavDisplay entry (back stack
+        // [Mutual]) right after prefillMatchFromGrid.
+        val vm = MutualViewModel(FakeSatelliteRepo(), FakeSettingsRepo())
+        vm.prefillMatchFromGrid("OL62")
+        composeRule.setContent {
+            val backStack = rememberNavBackStack(Screen.Mutual)
+            MaterialTheme {
+                Surface(modifier = Modifier.fillMaxSize()) {
+                    NavDisplay(
+                        backStack = backStack,
+                        onBack = { backStack.removeLastOrNull() },
+                        entryProvider = entryProvider {
+                            entry<Screen.Mutual> { MutualScreen(viewModel = vm) }
+                        }
+                    )
+                }
+            }
+        }
+        composeRule.waitForIdle()
+        composeRule.onNodeWithText("Time range").assertIsDisplayed()
+    }
+
+    @Test
+    fun navDisplay_switchToMutualEntry_scrollsToTimeRange() {
+        // Closest device path: start on the Map entry, then push the Mutual
+        // entry (what the map "Match" button does). NavDisplay runs a real
+        // fade transition while the Mutual screen composes.
+        val vm = MutualViewModel(FakeSatelliteRepo(), FakeSettingsRepo())
+        vm.prefillMatchFromGrid("OL62")
+        val backStackRef = mutableStateOf<NavBackStack<NavKey>?>(null)
+        composeRule.setContent {
+            val backStack = rememberNavBackStack(Screen.Map)
+            backStackRef.value = backStack
+            MaterialTheme {
+                Surface(modifier = Modifier.fillMaxSize()) {
+                    NavDisplay(
+                        backStack = backStack,
+                        onBack = { backStack.removeLastOrNull() },
+                        entryProvider = entryProvider {
+                            entry<Screen.Map> { Text("MAP PAGE") }
+                            entry<Screen.Mutual> { MutualScreen(viewModel = vm) }
+                        }
+                    )
+                }
+            }
+        }
+        composeRule.waitForIdle()
+        // Push Mutual like onMatchGrid does, so the transition composes
+        // MutualScreen with scrollToTimeRange already set.
+        composeRule.runOnIdle { backStackRef.value?.add(Screen.Mutual) }
+        composeRule.waitForIdle()
+        composeRule.onNodeWithText("Time range").assertIsDisplayed()
+    }
+
+    @Test
+    fun scrollRetriesUntilContentGrows() {
+        // Reproduces the real-device mechanism: the first frame's content
+        // (item 0 short) is shorter than the viewport, so scrollToItem(1) has
+        // no range and cannot move. Then the content grows (async results)
+        // past one screen; the retry loop must land on item 1.
+        composeRule.setContent {
+            MaterialTheme {
+                Surface(modifier = Modifier.fillMaxSize()) {
+                    val tall = mutableStateOf(false)
+                    LaunchedEffect(Unit) { delay(300); tall.value = true }
+                    val state = remember { LazyListState() }
+                    LaunchedEffect(state) {
+                        // Same retry loop MutualScreen uses for the prefill.
+                        for (attempt in 0 until 20) {
+                            state.scrollToItem(1)
+                            if (state.firstVisibleItemIndex == 1) return@LaunchedEffect
+                            delay(100)
+                        }
+                    }
+                    LazyColumn(state = state) {
+                        item {
+                            if (tall.value) Spacer(modifier = Modifier.height(900.dp))
+                            else Spacer(modifier = Modifier.height(40.dp))
+                        }
+                        item { Text("target-item") }
+                    }
+                }
+            }
+        }
+        composeRule.waitForIdle()
+        composeRule.onNodeWithText("target-item").assertIsDisplayed()
+        // Confirm the list really scrolled (station card equivalent is gone).
+        // We can't read listState from here, so use the VM-style probe: none —
+        // the target visible + viewport tall enough implies item 1 on top.
+    }
+
+    @Test
+    fun keepPositionAcrossTabs_thenMapMatchPrefill_scrollsToTimeRange() {
+        // User hypothesis: the "keep scroll position across tab switches"
+        // machinery (listState remember(queryGeneration) + snapshotFlow
+        // write-back) interferes with the prefill auto-scroll. Reproduce the
+        // full journey: first visit -> scroll a bit -> leave -> return
+        // (position restored) -> leave -> enter via map Match button.
+        val vm = MutualViewModel(FakeSatelliteRepo(), FakeSettingsRepo())
+        val showMutual = mutableStateOf(true)
+
+        // First visit (e.g. bottom nav), user scrolls a little; the
+        // snapshotFlow write-back stored index/offset in the VM.
+        composeRule.setContent {
+            MaterialTheme {
+                Surface(modifier = Modifier.fillMaxSize()) {
+                    if (showMutual.value) MutualScreen(viewModel = vm)
+                }
+            }
+        }
+        composeRule.waitForIdle()
+        vm.listScrollIndex = 0
+        vm.listScrollOffset = 40
+
+        // Leave the page (tab switch destroys the composition).
+        showMutual.value = false
+        composeRule.waitForIdle()
+
+        // Re-enter: keep-position restores the scroll offset.
+        showMutual.value = true
+        composeRule.waitForIdle()
+
+        // Leave again, then enter via the map grid-QSO Match button.
+        showMutual.value = false
+        composeRule.waitForIdle()
+        vm.prefillMatchFromGrid("OL62")
+        showMutual.value = true
+        composeRule.waitForIdle()
+
+        composeRule.onNodeWithText("Time range").assertIsDisplayed()
     }
 }

feature/mutual/src/test/java/com/rtbishop/look4sat/feature/mutual/MutualViewModelTest.kt

@@ -285,4 +285,39 @@ class MutualViewModelTest {
 
         assertNull(vm.uiState.value.errorMessage)
     }
+
+    @Test
+    fun `requery keeps scroll position and stale results while running`() = runTest(mainDispatcherRule.dispatcher.scheduler) {
+        val windows = TestOrbits.findPassWindows()
+        assertTrue("fixture must produce ISS windows", windows.isNotEmpty())
+        val vm = createVm(
+            satellites = listOf(TestOrbits.ISS),
+            passes = windows
+        )
+        vm.onStationBGrid("OL62")
+        queryAndSettle(vm)
+        assertTrue("fixture must yield passes", vm.uiState.value.mutualPasses.isNotEmpty())
+
+        // The user scrolled into the results; the snapshotFlow write-back has
+        // stored this position in the VM.
+        vm.listScrollIndex = 4
+        vm.listScrollOffset = 137
+
+        // Re-run the query from the match page ("query" button).
+        vm.queryMutualPasses()
+
+        // While the query runs, the old results stay on screen (the list keeps
+        // its height, so the scroll position is not clamped away)...
+        assertTrue("stale results kept while calculating", vm.uiState.value.mutualPasses.isNotEmpty())
+        // ...and the scroll position must not be reset to the top.
+        assertEquals(4, vm.listScrollIndex)
+        assertEquals(137, vm.listScrollOffset)
+
+        advanceUntilIdle()
+        assertFalse(vm.uiState.value.isCalculating)
+        assertTrue("fresh results replace the stale ones", vm.uiState.value.mutualPasses.isNotEmpty())
+        // Position intact after the query settled.
+        assertEquals(4, vm.listScrollIndex)
+        assertEquals(137, vm.listScrollOffset)
+    }
 }

gradle/libs.versions.toml

@@ -1,8 +1,8 @@
 [versions]
 #noinspection UnusedVersionCatalogEntry
-appVersionCode = "488"
+appVersionCode = "493"
 #noinspection UnusedVersionCatalogEntry
-appVersionName = "4.4.7-ba7opf.12.2"
+appVersionName = "4.4.7-ba7opf.13"
 #noinspection UnusedVersionCatalogEntry
 compileSdk = "37"
 #noinspection UnusedVersionCatalogEntry