build: bump to 4.4.7-ba7opf.14.1

- MapScreen: mark-a-station callsign input uppercases as you type
- MutualViewModel: read passesSettings.hoursBefore, shift the mutual
  match query start to now-hoursBefore so historical passes are
  included when the main Passes page has a lookback window set;
  endTime stays at now+hoursAhead

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)
                                 }
                             )
                         }

core/data/src/main/java/com/rtbishop/look4sat/core/data/repository/SettingsRepo.kt

@@ -269,6 +269,43 @@ class SettingsRepo(
         preferences.edit { putString(keyRoamedGrids, array.toString()) }
     }
 
+    // Marked stations in unworked gridsquares, persisted as a single JSON
+    // object: {"OL62":{"c":call,"t":epochMs}}. One mark per grid.
+    private val keyMarkedGridStations = "markedGridStations"
+
+    override fun getMarkedGridStations(): Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation> {
+        val json = preferences.getString(keyMarkedGridStations, null).orEmpty()
+        if (json.isBlank()) return emptyMap()
+        return try {
+            val root = org.json.JSONObject(json)
+            val result = mutableMapOf<String, com.rtbishop.look4sat.core.domain.model.MarkedStation>()
+            for (grid in root.keys()) {
+                val o = root.optJSONObject(grid) ?: continue
+                val call = o.optString("c").ifBlank { continue }
+                result[grid] = com.rtbishop.look4sat.core.domain.model.MarkedStation(
+                    call = call,
+                    epochMs = o.optLong("t")
+                )
+            }
+            result
+        } catch (_: Exception) {
+            emptyMap()
+        }
+    }
+
+    override fun setMarkedGridStations(stations: Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation>) {
+        val root = org.json.JSONObject()
+        for ((grid, station) in stations) {
+            root.put(
+                grid,
+                org.json.JSONObject()
+                    .put("c", station.call)
+                    .put("t", station.epochMs)
+            )
+        }
+        preferences.edit { putString(keyMarkedGridStations, root.toString()) }
+    }
+
     // LoTW credentials (stored locally on the device only)
     private val keyLoTWCall = "lotwCallsign"
     private val keyLoTWPass = "lotwPassword"

core/data/src/test/java/com/rtbishop/look4sat/core/data/repository/DatabaseRepoTest.kt

@@ -312,6 +312,10 @@ private class FakeSettingsRepo(dataSources: DataSourcesSettings = defaultDataSou
     override fun setRoamedGrids(grids: Set<String>) {
         roamedGrids.value = grids
     }
+
+    override fun getMarkedGridStations(): Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation> = emptyMap()
+
+    override fun setMarkedGridStations(stations: Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation>) = Unit
 }
 
 private fun defaultDataSourcesSettings(): DataSourcesSettings {

core/data/src/test/java/com/rtbishop/look4sat/core/data/repository/SelectionRepoSearchTest.kt

@@ -189,6 +189,8 @@ private class FakeSettingsRepoForSearch : ISettingsRepo {
     override fun setWorkedGridQsos(qsos: Map<String, List<com.rtbishop.look4sat.core.domain.model.GridQso>>) = Unit
     override fun getRoamedGrids(): Set<String> = emptySet()
     override fun setRoamedGrids(grids: Set<String>) = Unit
+    override fun getMarkedGridStations(): Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation> = emptyMap()
+    override fun setMarkedGridStations(stations: Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation>) = Unit
     override fun updateLoTWSettings(settings: com.rtbishop.look4sat.core.domain.model.LoTWSettings) = Unit
     override fun getLastLotwSyncDate(): String = ""
     override fun setLastLotwSyncDate(date: String) = Unit

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/model/MarkedStation.kt

@@ -0,0 +1,31 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.domain.model
+
+/**
+ * A station the user marked in a gridsquare they have NOT yet worked — a
+ * reminder to try to contact that callsign. Stored per 4-char grid (one mark
+ * per grid).
+ *
+ * @param call      the callsign the user wants to work (uppercase)
+ * @param epochMs   the moment the mark was created, UTC milliseconds
+ */
+data class MarkedStation(
+    val call: String,
+    val epochMs: Long
+)

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/repository/ISettingsRepo.kt

@@ -105,6 +105,11 @@ interface ISettingsRepo {
     /** Distinct 4-char gridsquares the account operated from (LoTW <MY_GRIDSQUARE>). */
     fun getRoamedGrids(): Set<String>
     fun setRoamedGrids(grids: Set<String>)
+    /** Stations the user marked as "want to contact" in unworked gridsquares
+     *  (grid -> mark). One mark per grid; cleared automatically when the grid
+     *  becomes worked. */
+    fun getMarkedGridStations(): Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation>
+    fun setMarkedGridStations(stations: Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation>)
     //endregion
 
     //region # LoTW confirmed-grids settings

core/domain/src/test/java/com/rtbishop/look4sat/core/domain/repository/LoTWGridSyncTest.kt

@@ -21,6 +21,7 @@ import com.rtbishop.look4sat.core.domain.model.DatabaseState
 import com.rtbishop.look4sat.core.domain.model.DataSourcesSettings
 import com.rtbishop.look4sat.core.domain.model.GridQso
 import com.rtbishop.look4sat.core.domain.model.LoTWSettings
+import com.rtbishop.look4sat.core.domain.model.MarkedStation
 import com.rtbishop.look4sat.core.domain.model.OtherSettings
 import com.rtbishop.look4sat.core.domain.model.PassesSettings
 import com.rtbishop.look4sat.core.domain.model.RCSettings
@@ -261,6 +262,9 @@ class LoTWGridSyncTest {
         override fun setWorkedGridQsos(qsos: Map<String, List<GridQso>>) { workedGridQsos = qsos }
         override fun getRoamedGrids(): Set<String> = roamedGrids
         override fun setRoamedGrids(grids: Set<String>) { roamedGrids = grids }
+        private var markedGridStations: Map<String, MarkedStation> = emptyMap()
+        override fun getMarkedGridStations(): Map<String, MarkedStation> = markedGridStations
+        override fun setMarkedGridStations(stations: Map<String, MarkedStation>) { markedGridStations = stations }
         override fun getLastLotwSyncDate(): String = lastSyncDate
         override fun setLastLotwSyncDate(date: String) { lastSyncDate = date }
         override fun getLastLotwSyncCallsign(): String = lastSyncCallsign

core/presentation/src/main/res/values-zh/strings.xml

@@ -131,6 +131,12 @@
     <string name="grid_qso_first">首通</string>
     <string name="grid_qso_no_sat">卫星未知</string>
     <string name="grid_qso_match">匹配</string>
+    <!-- 未通联网格中的“标记想通联的电台”提醒 -->
+    <string name="grid_mark_station">标记你想通联的电台</string>
+    <string name="grid_mark_callsign">呼号</string>
+    <string name="grid_mark_confirm">标记</string>
+    <string name="grid_mark_label">标记</string>
+    <string name="grid_mark_delete">删除标记</string>
     <string name="map_visible">日照中</string>
 
     <!-- Settings screen -->

core/presentation/src/main/res/values/strings.xml

@@ -151,6 +151,12 @@
     <string name="grid_qso_first">First</string>
     <string name="grid_qso_no_sat">satellite unknown</string>
     <string name="grid_qso_match">Match</string>
+    <!-- Mark-a-station reminder in unworked grids -->
+    <string name="grid_mark_station">Mark a station you want to contact</string>
+    <string name="grid_mark_callsign">Callsign</string>
+    <string name="grid_mark_confirm">Mark</string>
+    <string name="grid_mark_label">Marked</string>
+    <string name="grid_mark_delete">Remove mark</string>
     <string name="map_visible">Visible</string>
 
     <!-- Settings screen -->

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

@@ -64,6 +64,11 @@ class MaidenheadGridOverlay : Overlay() {
         style = android.graphics.Paint.Style.FILL
         color = Color.argb(90, 76, 217, 100)
     }
+    // 标记(想通联)网格填充: 红色, 透明度与绿色 workedPaint 一致(alpha 90).
+    private val markedPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
+        style = android.graphics.Paint.Style.FILL
+        color = Color.argb(90, 255, 59, 48)
+    }
     private val roamStripePaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
         style = Paint.Style.STROKE
         strokeWidth = 14f
@@ -87,6 +92,11 @@ class MaidenheadGridOverlay : Overlay() {
     /** Worked gridsquares (4-char, uppercase) to highlight, e.g. {"OL62", "PM95"}. */
     var workedGrids: Set<String> = emptySet()
 
+    /** Marked gridsquares (4-char, uppercase) — unworked grids the user has
+     *  marked a station they want to contact in; drawn red, same alpha as the
+     *  green worked fill. Value carries the marked callsign for label mode. */
+    var markedGrids: Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation> = emptyMap()
+
     /** Grid-mode first-call labels: label worked (green) cells with the first
      *  callsign worked in that grid instead of the Maidenhead code; non-worked
      *  cells get no label at all. Only meaningful at sub-square zoom. */
@@ -189,6 +199,9 @@ class MaidenheadGridOverlay : Overlay() {
                         if (cellLabel(lat, lon, zoom) in workedGrids) {
                             canvas.drawRect(xLeft, yTop, xRight, yBottom, workedPaint)
                         }
+                        if (cellLabel(lat, lon, zoom) in markedGrids) {
+                            canvas.drawRect(xLeft, yTop, xRight, yBottom, markedPaint)
+                        }
                     }
                 }
             } else {
@@ -215,6 +228,22 @@ class MaidenheadGridOverlay : Overlay() {
                         canvas.drawRect(xLeft, yTop, xRight, yBottom, workedPaint)
                     }
                 }
+                for (grid in markedGrids.keys) {
+                    val cell = gridCellBounds(grid) ?: continue
+                    for (turn in -colRepeats..colRepeats) {
+                        val dLon = turn * 360.0
+                        if (cell.lonRight + dLon <= leftLon || cell.lonLeft + dLon >= rightLon) continue
+                        val yTop = projectionToY(projection, cell.latTop) ?: continue
+                        val yBottom = projectionToY(projection, cell.latBottom) ?: continue
+                        val xLeftBase = projectionToX(projection, cell.lonLeft, centerLon, worldWidthPx) ?: continue
+                        val xRightBase = projectionToX(projection, cell.lonRight, centerLon, worldWidthPx) ?: continue
+                        val xLeft = xLeftBase + turn * worldWidthPx.toFloat()
+                        val xRight = xRightBase + turn * worldWidthPx.toFloat()
+                        if (xRight < 0f || xLeft > canvas.width) continue
+                        if (yBottom < 0f || yTop > canvas.height) continue
+                        canvas.drawRect(xLeft, yTop, xRight, yBottom, markedPaint)
+                    }
+                }
             }
         }
 
@@ -414,12 +443,15 @@ class MaidenheadGridOverlay : Overlay() {
                 if (xRight < 0f || xLeft > canvas.width) continue
                 val label = cellLabel(lat, lon, zoom)
                 if (showFirstCallLabels) {
-                    // 首通呼号模式: 只有绿格(worked)标注该格第一个通联的呼号,
+                    // 首通呼号模式: 绿格(worked)标注该格第一个通联的呼号, 红格(marked)
-                    // 非绿格空着不写网格字符.
+                    // 标注用户标记想通联的呼号, 均淡黄文字; 其它格空着不写网格字符.
-                    if (label in workedGrids) {
+                    when {
-                        firstCallsByGrid[label]?.let { call ->
+                        label in workedGrids -> firstCallsByGrid[label]?.let { call ->
                             canvas.drawText(call, (xLeft + xRight) / 2f, yCenter, firstCallPaint)
                         }
+                        label in markedGrids -> markedGrids[label]?.let { station ->
+                            canvas.drawText(station.call, (xLeft + xRight) / 2f, yCenter, firstCallPaint)
+                        }
                     }
                 } else {
                     canvas.drawText(label, (xLeft + xRight) / 2f, yCenter, labelPaint)

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"
@@ -357,7 +362,8 @@ private fun MapScreen(
                             centerOnStation = shouldCenter,
                             // 首通呼号标签只作用于 VUCC 视图(用户要求); "All"/其他奖状不过滤.
                             showFirstCallLabels = uiState.showFirstCallLabels && selectedAward == AwardType.VUCC,
-                            firstCallsByGrid = firstCallsByGrid
+                            firstCallsByGrid = firstCallsByGrid,
+                            markedGrids = uiState.markedGrids
                         )
                         if (!shouldCenter || uiState.stationPosition != null) {
                             prevGridMode = uiState.isGridMode
@@ -417,14 +423,19 @@ private fun MapScreen(
         }
     }
     // Centered dialog listing the tapped worked grid's confirmed satellite QSOs.
-    // Dismissed by tapping outside (no explicit close button).
+    // Dismissed by tapping outside (no explicit close button). Unworked grids
+    // open the same dialog with an empty list plus a mark-a-station reminder.
     selectedGrid?.let { grid ->
         WorkedGridQsoDialog(
             grid = grid,
             qsos = uiState.workedGridQsos[grid].orEmpty().sortedBy { it.epochMs },
+            marked = uiState.markedGrids[grid],
             isUtc = uiState.isUtc,
+            matchCalculating = matchCalculating,
             onDismiss = { selectedGrid = null },
-            onMatch = { onMatchGrid(grid) }
+            onMatch = { onMatchGrid(grid) },
+            onMark = { call -> onAction(MapAction.SetMarkedStation(grid, call)) },
+            onRemoveMark = { onAction(MapAction.RemoveMarkedStation(grid)) }
         )
     }
 }
@@ -435,10 +446,16 @@ private fun MapScreen(
 private fun WorkedGridQsoDialog(
     grid: String,
     qsos: List<com.rtbishop.look4sat.core.domain.model.GridQso>,
+    marked: com.rtbishop.look4sat.core.domain.model.MarkedStation?,
     isUtc: Boolean,
+    matchCalculating: Boolean,
     onDismiss: () -> Unit,
-    onMatch: () -> Unit
+    onMatch: () -> Unit,
+    onMark: (String) -> Unit,
+    onRemoveMark: () -> Unit
 ) {
+    var showMarkInput by remember { mutableStateOf(false) }
+    var callInput by remember { mutableStateOf("") }
     androidx.compose.ui.window.Dialog(onDismissRequest = onDismiss) {
         // Centered card, ~85% width, internal scroll for long lists.
         Card(
@@ -467,41 +484,150 @@ 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))
                     }
                 }
                 androidx.compose.material3.HorizontalDivider()
-                if (qsos.isNotEmpty()) {
+                Column(
-                    // Group by callsign preserving first-contact order (list is
+                    Modifier
-                    // already sorted oldest-first); expandable rows.
+                        .heightIn(max = 380.dp)
-                    val grouped = remember(qsos) {
+                        .verticalScroll(rememberScrollState())
-                        qsos.groupBy { it.call }.entries.sortedBy { it.value.first().epochMs }
+                ) {
+                    // A marked station shows first as a red reminder row: red
+                    // callsign, "标记" in the count column, the marking date in
+                    // the date column, and a small delete icon to remove it.
+                    if (marked != null) {
+                        MarkedStationRow(marked = marked, isUtc = isUtc, onRemoveMark = onRemoveMark)
+                        androidx.compose.material3.HorizontalDivider(color = MaterialTheme.colorScheme.outlineVariant.copy(alpha = 0.3f))
                     }
-                    Column(
+                    if (qsos.isNotEmpty()) {
-                        Modifier
+                        // Group by callsign preserving first-contact order (list is
-                            .heightIn(max = 380.dp)
+                        // already sorted oldest-first); expandable rows.
-                            .verticalScroll(rememberScrollState())
+                        val grouped = remember(qsos) {
-                    ) {
+                            qsos.groupBy { it.call }.entries.sortedBy { it.value.first().epochMs }
+                        }
                         grouped.forEach { (call, callQsos) ->
                             WorkedGridCallRow(call, callQsos = callQsos, isUtc = isUtc)
                             androidx.compose.material3.HorizontalDivider(color = MaterialTheme.colorScheme.outlineVariant.copy(alpha = 0.3f))
                         }
                     }
+                    // Unworked grids: offer to mark a station the user wants to
+                    // contact in this grid (a reminder, cleared when worked).
+                    if (qsos.isEmpty()) {
+                        TextButton(
+                            onClick = {
+                                callInput = marked?.call.orEmpty()
+                                showMarkInput = true
+                            },
+                            modifier = Modifier.fillMaxWidth()
+                        ) {
+                            Icon(
+                                painter = painterResource(R.drawable.ic_add),
+                                contentDescription = null,
+                                modifier = Modifier.size(18.dp)
+                            )
+                            Spacer(Modifier.width(4.dp))
+                            Text(stringResource(R.string.grid_mark_station))
+                        }
+                    }
                 }
             }
         }
     }
+    // Mark-a-station input dialog: enter a callsign as a reminder.
+    if (showMarkInput) {
+        androidx.compose.material3.AlertDialog(
+            onDismissRequest = { showMarkInput = false },
+            title = { Text(stringResource(R.string.grid_mark_station)) },
+            text = {
+                androidx.compose.material3.OutlinedTextField(
+                    value = callInput,
+                    onValueChange = { callInput = it.uppercase() },
+                    label = { Text(stringResource(R.string.grid_mark_callsign)) },
+                    singleLine = true
+                )
+            },
+            confirmButton = {
+                TextButton(
+                    enabled = callInput.isNotBlank(),
+                    onClick = {
+                        onMark(callInput)
+                        showMarkInput = false
+                    }
+                ) { Text(stringResource(R.string.grid_mark_confirm)) }
+            },
+            dismissButton = {
+                TextButton(onClick = { showMarkInput = false }) { Text(stringResource(R.string.btn_cancel)) }
+            }
+        )
+    }
+}
+
+@Composable
+private fun MarkedStationRow(
+    marked: com.rtbishop.look4sat.core.domain.model.MarkedStation,
+    isUtc: Boolean,
+    onRemoveMark: () -> Unit
+) {
+    Row(
+        verticalAlignment = Alignment.CenterVertically,
+        modifier = Modifier.fillMaxWidth().padding(horizontal = 16.dp, vertical = 8.dp)
+    ) {
+        Text(
+            text = marked.call,
+            style = MaterialTheme.typography.titleMedium,
+            fontFamily = androidx.compose.ui.text.font.FontFamily.Monospace,
+            color = ComposeColor(0xFFFF3B30),
+            maxLines = 1,
+            overflow = androidx.compose.ui.text.style.TextOverflow.Ellipsis,
+            modifier = Modifier.weight(1f)
+        )
+        Text(
+            text = stringResource(R.string.grid_mark_label),
+            style = MaterialTheme.typography.bodySmall,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+            textAlign = androidx.compose.ui.text.style.TextAlign.Center,
+            modifier = Modifier.weight(1f)
+        )
+        Row(
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.End,
+            modifier = Modifier.weight(1f)
+        ) {
+            Text(
+                text = formatDate(marked.epochMs, isUtc),
+                style = MaterialTheme.typography.bodySmall,
+                color = MaterialTheme.colorScheme.onSurfaceVariant
+            )
+            Icon(
+                painter = painterResource(R.drawable.ic_delete),
+                contentDescription = stringResource(R.string.grid_mark_delete),
+                tint = MaterialTheme.colorScheme.error,
+                modifier = Modifier
+                    .size(18.dp)
+                    .clickable(onClick = onRemoveMark)
+            )
+        }
+    }
 }
 
 @Composable
@@ -929,7 +1055,8 @@ private fun setGridMode(
     stationPosition: GeoPos?,
     centerOnStation: Boolean = false,
     showFirstCallLabels: Boolean = false,
-    firstCallsByGrid: Map<String, String> = emptyMap()
+    firstCallsByGrid: Map<String, String> = emptyMap(),
+    markedGrids: Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation> = emptyMap()
 ) {
     try {
         val gridOverlay = mapView.overlays[OVERLAY_GRID]
@@ -940,6 +1067,7 @@ private fun setGridMode(
             // 首通呼号模式: 绿格标注第一个通联的呼号, 非绿格不显示标签.
             gridOverlay.showFirstCallLabels = showFirstCallLabels
             gridOverlay.firstCallsByGrid = firstCallsByGrid
+            gridOverlay.markedGrids = markedGrids
             // ownGrid must be set on EVERY update — the position is available
             // regardless of whether this frame centers (centering happens only
             // on entry, but passing null here would wipe the bold outline).
@@ -951,6 +1079,7 @@ private fun setGridMode(
                 this.roamedGrids = roamedGrids
                 this.showFirstCallLabels = showFirstCallLabels
                 this.firstCallsByGrid = firstCallsByGrid
+                this.markedGrids = markedGrids
                 this.ownGrid = ownGridOf(stationPosition)
             }
         }

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

@@ -34,6 +34,8 @@ data class MapState(
     val workedGridQsos: Map<String, List<com.rtbishop.look4sat.core.domain.model.GridQso>> = emptyMap(),
     /** 4-char gridsquares the station operated from (LoTW MY_GRIDSQUARE) — blue stripes. */
     val roamedGrids: Set<String> = emptySet(),
+    /** Stations the user marked in unworked gridsquares (grid -> mark) — red fill. */
+    val markedGrids: Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation> = emptyMap(),
     val stationPosition: GeoPos? = null,
     val orbitalPass: OrbitalPass,
     val track: List<List<GeoPos>>? = null,
@@ -52,6 +54,8 @@ sealed interface MapAction {
     data class SelectDefaultItem(val catnum: Int) : MapAction
     data class ToggleGridMode(val value: Boolean) : MapAction
     data class ToggleFirstCallLabels(val value: Boolean) : MapAction
+    data class SetMarkedStation(val grid: String, val call: String) : MapAction
+    data class RemoveMarkedStation(val grid: String) : MapAction
     data class SetVisible(val isVisible: Boolean) : MapAction
 }
 

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

@@ -90,11 +90,19 @@ class MapViewModel(
         }
         viewModelScope.launch {
             settingsRepo.wavelogSettings.collectLatest { _ ->
+                val workedGrids = settingsRepo.getWorkedGrids()
+                val markedGrids = settingsRepo.getMarkedGridStations()
+                // Marked stations auto-clear once their grid becomes worked:
+                // the reminder has served its purpose (user req: 网格变绿后标记自动清除).
+                val stale = markedGrids.keys.filter { it in workedGrids }
+                val activeMarks = if (stale.isEmpty()) markedGrids else markedGrids - stale.toSet()
+                if (stale.isNotEmpty()) settingsRepo.setMarkedGridStations(activeMarks)
                 _uiState.update {
                     it.copy(
-                        workedGrids = settingsRepo.getWorkedGrids(),
+                        workedGrids = workedGrids,
                         workedGridQsos = settingsRepo.getWorkedGridQsos(),
-                        roamedGrids = settingsRepo.getRoamedGrids()
+                        roamedGrids = settingsRepo.getRoamedGrids(),
+                        markedGrids = activeMarks
                     )
                 }
             }
@@ -112,6 +120,20 @@ class MapViewModel(
             is MapAction.SelectDefaultItem -> selectDefaultSatellite(action.catnum)
             is MapAction.ToggleGridMode -> settingsRepo.updateOtherSettings { it.copy(stateOfMapGrid = action.value) }
             is MapAction.ToggleFirstCallLabels -> settingsRepo.updateOtherSettings { it.copy(stateOfMapFirstCall = action.value) }
+            is MapAction.SetMarkedStation -> {
+                val updated = settingsRepo.getMarkedGridStations() +
+                    (action.grid to com.rtbishop.look4sat.core.domain.model.MarkedStation(
+                        call = action.call.trim().uppercase(),
+                        epochMs = System.currentTimeMillis()
+                    ))
+                settingsRepo.setMarkedGridStations(updated)
+                _uiState.update { it.copy(markedGrids = updated) }
+            }
+            is MapAction.RemoveMarkedStation -> {
+                val updated = settingsRepo.getMarkedGridStations() - action.grid
+                settingsRepo.setMarkedGridStations(updated)
+                _uiState.update { it.copy(markedGrids = updated) }
+            }
             is MapAction.SetVisible -> isScreenVisible.value = action.isVisible
         }
     }

feature/mutual/build.gradle.kts

@@ -4,4 +4,20 @@ plugins {
 
 android {
     namespace = "com.rtbishop.look4sat.feature.mutual"
-}
+    testOptions {
+        unitTests {
+            // Robolectric needs real Android resources for Compose UI tests.
+            isIncludeAndroidResources = true
+        }
+    }
+}
+
+dependencies {
+    testImplementation(libs.test.junit4)
+    testImplementation(libs.test.coroutines)
+    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=$listReady")
+
     LazyColumn(
-        modifier = Modifier.fillMaxSize(),
+        modifier = Modifier
+            .fillMaxSize()
+            .onGloballyPositioned {
+                if (!listReady) {
+                    Log.d(TAG, "lazy list laid out, opening prefill scroll gate")
+                    listReady = true
+                }
+            },
         state = listState,
         verticalArrangement = Arrangement.spacedBy(6.dp)
     ) {
@@ -369,8 +389,44 @@ private fun MutualContent(
             )
         }
     }
+
+    // Prefill from the map's grid-QSO dialog "Match" button: once the page is
+    // laid out, jump straight to the time-range card. Index accounts for the
+    // optional error card at the top (error = 0, station inputs = 1, time
+    // range = 2; else 1). scrollToItem is used instead of initializing the
+    // LazyListState at index 1: the constructor parameter is ignored by this
+    // Compose version (verified in tests), while scrollToItem lands correctly.
+    val matchSearchIndex = if (state.errorMessage != null) 2 else 1
+    LaunchedEffect(state.scrollToTimeRange, matchSearchIndex, listReady) {
+        Log.d(TAG, "scroll effect: scrollToTimeRange=${state.scrollToTimeRange} matchIndex=$matchSearchIndex listReady=$listReady")
+        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 = "",
@@ -50,12 +52,24 @@ data class MutualUiState(
     val stationBGrid: String = "",
     val stationBMinElev: Double = 10.0,
     val hoursAhead: Int = 24,
+    /** 历史过境回看窗口(小时), 跟随主页面 Passes 设置; 匹配查询从
+     *  now-hoursBefore 开始, 使设置过历史回看时匹配页也包含历史过境. */
+    val hoursBefore: Int = 0,
     val mutualPasses: List<MutualPass> = emptyList(),
     val isCalculating: Boolean = false,
     val hasSearched: Boolean = false,
     val selectedPassIndex: Int = -1,
     val isUtc: Boolean = false,
-    val errorMessage: String? = null
+    val errorMessage: String? = null,
+    // 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,
+    // 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(
@@ -97,6 +111,12 @@ class MutualViewModel(
                 _uiState.update { it.copy(isUtc = settings.stateOfUtc) }
             }
         }
+        // 历史过境回看窗口跟随主页面 Passes 设置 (设置里改小时数, 匹配页同步生效)
+        viewModelScope.launch {
+            settingsRepo.passesSettings.collectLatest { settings ->
+                _uiState.update { it.copy(hoursBefore = settings.hoursBefore) }
+            }
+        }
     }
 
     fun onStationALat(value: String) {
@@ -187,25 +207,46 @@ class MutualViewModel(
      * Pre-fill the match page for a target grid picked from the map's grid-QSO
      * dialog ("Match" button): set the opposite-station grid (with its
      * coordinates), reset the time range to 24h, start the query immediately
-     * so results are ready when the page opens, and position the list at the
+     * so results are ready when the page opens, and flag the page to scroll
-     * time-range card (LazyColumn item 1, the card right below the station
+     * straight to the time-range card once it is laid out.
-     * inputs) so the page opens showing it at the top.
      */
     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
+                hoursAhead = 24,
+                scrollToTimeRange = true,
+                pendingNavigation = true
             )
         }
-        queryMutualPasses(initialScrollIndex = 1)
+        queryMutualPasses()
     }
 
-    fun queryMutualPasses(initialScrollIndex: Int = 0) {
+    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) }
+    }
+
+    /**
+     * 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
@@ -228,26 +269,39 @@ 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 {
-            val time = System.currentTimeMillis()
+            val now = System.currentTimeMillis()
+            // 历史回看: 查询窗口起点 = now - hoursBefore (跟随主页面 Passes 设置),
+            // 终点 = now + hoursAhead 不变.
+            val time = now - state.hoursBefore * 60L * 60L * 1000L
             val minElevA = state.stationAMinElev
             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, state.hoursBefore)
+                }
+            } 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()) {
@@ -286,9 +340,11 @@ class MutualViewModel(
         satellites: List<OrbitalObject>,
         posA: GeoPos, posB: GeoPos,
         minElevADeg: Double, minElevBDeg: Double,
-        time: Long, hours: Int
+        time: Long, hours: Int, hoursBefore: Int
     ): List<MutualPass> {
-        val endTime = time + hours * 60L * 60L * 1000L
+        // 终点始终是 now + hoursAhead; 起点已由调用方下移 hoursBefore 小时,
+        // 因此这里的 endTime 要在起点之上补回 hoursBefore, 保证窗口 = [now-hb, now+h].
+        val endTime = time + (hoursBefore + hours) * 60L * 60L * 1000L
         val sampleInterval = 5_000L
 
         // Use the main page's pass list for AOS/LOS times, then sample the curves

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

@@ -115,6 +115,8 @@ class FakeSettingsRepo(initialPosition: GeoPos = GeoPos(23.13, 113.26)) : ISetti
     override fun setWorkedGridQsos(qsos: Map<String, List<GridQso>>) = TODO()
     override fun getRoamedGrids(): Set<String> = TODO()
     override fun setRoamedGrids(grids: Set<String>) = TODO()
+    override fun getMarkedGridStations(): Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation> = emptyMap()
+    override fun setMarkedGridStations(stations: Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation>) = Unit
     override fun updateLoTWSettings(settings: LoTWSettings) = TODO()
     override fun getLastLotwSyncDate(): String = ""
     override fun setLastLotwSyncDate(date: String) = Unit

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

@@ -0,0 +1,291 @@
+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
+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
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+import org.robolectric.annotation.GraphicsMode
+
+/**
+ * Verifies the map grid-QSO dialog "Match" prefill: after
+ * [MutualViewModel.prefillMatchFromGrid] the page opens with the time-range
+ * card at the top and the 24h query auto-started.
+ *
+ * Note: `LazyListState(firstVisibleItemIndex = 1)` is deliberately NOT used to
+ * position the page. In this Compose version (BOM 2026.06.01 / ui 1.11.x) the
+ * constructor parameter is ignored — the list still starts at item 0 — while
+ * `listState.scrollToItem(1)` from a LaunchedEffect lands correctly. See
+ * [scrollToItemLandsAtTop] below, which guards the scrollToItem mechanism.
+ *
+ * Robolectric quirk: `assertIsNotDisplayed()` is unreliable here (a node
+ * scrolled fully out of the viewport can still report "displayed"), so the
+ * prefill test asserts the time-range card IS displayed (positive assertion)
+ * rather than that the station card is NOT.
+ */
+@RunWith(RobolectricTestRunner::class)
+@GraphicsMode(GraphicsMode.Mode.NATIVE)
+@Config(sdk = [34], qualifiers = "w411dp-h891dp-port")
+class MutualMatchPrefillScrollTest {
+
+    @get:Rule
+    val composeRule = createComposeRule()
+
+    @Test
+    fun sanity_textRenders() {
+        composeRule.setContent {
+            MaterialTheme {
+                Text("sanity-check-text")
+            }
+        }
+        composeRule.onNodeWithText("sanity-check-text").assertIsDisplayed()
+    }
+
+    @Test
+    fun scrollToItemLandsAtTop() {
+        // Guards the mechanism the prefill relies on: scrollToItem(1) from a
+        // LaunchedEffect moves item 1 to the top of the viewport.
+        composeRule.setContent {
+            MaterialTheme {
+                Surface(modifier = Modifier.fillMaxSize()) {
+                    val state = remember { LazyListState(firstVisibleItemIndex = 0) }
+                    LaunchedEffect(Unit) { state.scrollToItem(1) }
+                    LazyColumn(state = state) {
+                        item { Text("min-item-0") }
+                        item { Text("min-item-1") }
+                        item { Text("min-item-2") }
+                    }
+                }
+            }
+        }
+        composeRule.waitForIdle()
+        composeRule.onNodeWithText("min-item-1").assertIsDisplayed()
+    }
+
+    @Test
+    fun defaultOpen_showsStationInputsAtTop() {
+        val vm = MutualViewModel(FakeSatelliteRepo(), FakeSettingsRepo())
+        composeRule.setContent {
+            MaterialTheme {
+                Surface(modifier = Modifier.fillMaxSize()) {
+                    MutualScreen(viewModel = vm)
+                }
+            }
+        }
+        // Without a prefill the list starts at item 0 (station inputs).
+        composeRule.onNodeWithText("Your Station").assertIsDisplayed()
+    }
+
+    @Test
+    fun prefillFromMap_opensAtTimeRangeCard() {
+        val vm = MutualViewModel(FakeSatelliteRepo(), FakeSettingsRepo())
+        // Same call the map grid-QSO "Match" button makes.
+        vm.prefillMatchFromGrid("OL62")
+
+        composeRule.setContent {
+            MaterialTheme {
+                Surface(modifier = Modifier.fillMaxSize()) {
+                    MutualScreen(viewModel = vm)
+                }
+            }
+        }
+
+        composeRule.waitForIdle()
+
+        // 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
+    fun prefillAutoStartsQueryAndFillsState() {
+        val vm = MutualViewModel(FakeSatelliteRepo(), FakeSettingsRepo())
+        vm.prefillMatchFromGrid("OL62")
+        val s = vm.uiState.value
+        // Query auto-started: with the empty-satellite fake the query reaches
+        // the "no satellite data" guard (rather than never being triggered),
+        // proving prefillMatchFromGrid kicks off queryMutualPasses.
+        assertTrue(
+            "auto-query should reach the satellite guard: gridA=${s.stationAGrid} " +
+                "gridB=${s.stationBGrid} err=${s.errorMessage}",
+            s.errorMessage?.contains("satellite", ignoreCase = true) == true
+        )
+        // ...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 = "487"
+appVersionCode = "495"
 #noinspection UnusedVersionCatalogEntry
-appVersionName = "4.4.7-ba7opf.12.1"
+appVersionName = "4.4.7-ba7opf.14.1"
 #noinspection UnusedVersionCatalogEntry
 compileSdk = "37"
 #noinspection UnusedVersionCatalogEntry
@@ -33,6 +33,8 @@ other-okhttp = "5.4.0"
 other-osmdroid = "6.1.20"
 
 test-junit4 = "4.13.2"
+robolectric = "4.16"
+androidx-test-core = "1.7.0"
 
 androidTest-junit = "1.3.0"
 androidTest-espresso = "3.7.0"
@@ -79,6 +81,9 @@ other-osmdroid = { module = "org.osmdroid:osmdroid-android", version.ref = "othe
 
 test-coroutines = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-test", version.ref = "kotlin-coroutines" }
 test-junit4 = { module = "junit:junit", version.ref = "test-junit4" }
+robolectric = { module = "org.robolectric:robolectric", version.ref = "robolectric" }
+androidx-test-core = { module = "androidx.test:core-ktx", version.ref = "androidx-test-core" }
+compose-ui-test-junit4 = { group = "androidx.compose.ui", name = "ui-test-junit4" }
 # Real org.json for unit tests (android.jar stub throws "not mocked")
 test-json = { module = "org.json:json", version = "20240303" }