fix: clear mainWindow reference on window destroy (#587)

The mainWindow variable was never cleared when the window was destroyed,
unlike settingsWindow which had a proper 'closed' handler. This caused
getMainWindow() to return a destroyed window object, preventing the
activate handler from correctly detecting the main window was gone and
creating a new one.

Fixes #587

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

application/state/useSettingsState.ts

@@ -33,7 +33,7 @@ import {
   STORAGE_KEY_GLOBAL_HOTKEY_ENABLED,
   STORAGE_KEY_AUTO_UPDATE_ENABLED,
   STORAGE_KEY_WORKSPACE_FOCUS_STYLE,
-  STORAGE_KEY_IMMERSIVE_MODE,
+
 } from '../../infrastructure/config/storageKeys';
 import { DEFAULT_UI_LOCALE, resolveSupportedLocale } from '../../infrastructure/config/i18n';
 import { TERMINAL_THEMES } from '../../infrastructure/config/terminalThemes';
@@ -340,20 +340,11 @@ export const useSettingsState = () => {
     }
   }, []);
 
-  const [immersiveMode, setImmersiveModeState] = useState<boolean>(() => {
-    const stored = localStorageAdapter.readString(STORAGE_KEY_IMMERSIVE_MODE);
-    if (stored === null || stored === '') {
-      // Persist default so collectSyncableSettings() can include it
-      localStorageAdapter.writeString(STORAGE_KEY_IMMERSIVE_MODE, 'true');
-      return true;
-    }
-    return stored === 'true';
-  });
-  const setImmersiveMode = useCallback((enabled: boolean) => {
-    setImmersiveModeState(enabled);
-    localStorageAdapter.writeString(STORAGE_KEY_IMMERSIVE_MODE, String(enabled));
-    notifySettingsChanged(STORAGE_KEY_IMMERSIVE_MODE, enabled);
-  }, [notifySettingsChanged]);
+  // Immersive mode is always enabled — the toggle has been removed from settings
+  const immersiveMode = true;
+  const setImmersiveMode = useCallback((_enabled: boolean) => {
+    // no-op: immersive mode is always on
+  }, []);
 
   const setSftpTransferConcurrency = useCallback((value: number) => {
     const clamped = Math.max(1, Math.min(16, Math.round(value)));
@@ -465,14 +456,6 @@ export const useSettingsState = () => {
     const storedDefaultViewMode = readStoredString(STORAGE_KEY_SFTP_DEFAULT_VIEW_MODE);
     if (storedDefaultViewMode === 'list' || storedDefaultViewMode === 'tree') setSftpDefaultViewMode(storedDefaultViewMode);
 
-    // Immersive mode
-    const storedImmersive = readStoredString(STORAGE_KEY_IMMERSIVE_MODE);
-    if (storedImmersive === 'true' || storedImmersive === 'false') {
-      const val = storedImmersive === 'true';
-      setImmersiveModeState(val);
-      notifySettingsChanged(STORAGE_KEY_IMMERSIVE_MODE, val);
-    }
-
     // Workspace focus style
     const storedFocusStyle = readStoredString(STORAGE_KEY_WORKSPACE_FOCUS_STYLE);
     if (storedFocusStyle === 'dim' || storedFocusStyle === 'border') setWorkspaceFocusStyleState(storedFocusStyle);
@@ -625,9 +608,6 @@ export const useSettingsState = () => {
           setSftpDefaultViewMode((prev) => (prev === value ? prev : value));
         }
       }
-      if (key === STORAGE_KEY_IMMERSIVE_MODE && typeof value === 'boolean') {
-        setImmersiveModeState((prev) => (prev === value ? prev : value));
-      }
       if (key === STORAGE_KEY_WORKSPACE_FOCUS_STYLE && (value === 'dim' || value === 'border')) {
         setWorkspaceFocusStyleState((prev) => (prev === value ? prev : value));
       }
@@ -849,13 +829,6 @@ export const useSettingsState = () => {
           setAutoUpdateEnabled(newValue);
         }
       }
-      // Sync immersive mode from other windows
-      if (e.key === STORAGE_KEY_IMMERSIVE_MODE && e.newValue !== null) {
-        const newValue = e.newValue === 'true';
-        if (newValue !== s.immersiveMode) {
-          setImmersiveModeState(newValue);
-        }
-      }
       // Sync workspace focus style from other windows
       if (e.key === STORAGE_KEY_WORKSPACE_FOCUS_STYLE && e.newValue !== null) {
         if (e.newValue === 'dim' || e.newValue === 'border') {

components/TerminalLayer.tsx

@@ -1452,13 +1452,12 @@ const TerminalLayerInner: React.FC<TerminalLayerProps> = ({
   }, [applyTerminalPreviewVars, themePreview]);
 
   useEffect(() => {
-    const themeToApply = activeTopTabsThemeId || (previewTargetSessionId ? focusedThemeId : null);
-    if (themeToApply) {
-      applyTopTabsPreviewVars(themeToApply);
-    } else {
-      clearTopTabsPreviewVars();
+    if (activeTopTabsThemeId) {
+      applyTopTabsPreviewVars(activeTopTabsThemeId);
+      return;
     }
-  }, [activeTopTabsThemeId, focusedThemeId, previewTargetSessionId, applyTopTabsPreviewVars]);
+    clearTopTabsPreviewVars();
+  }, [activeTopTabsThemeId, applyTopTabsPreviewVars]);
 
   useEffect(() => {
     const panelOpen = activeSidePanelTab === 'theme' && !!previewTargetSessionId;

components/settings/tabs/SettingsAppearanceTab.tsx

@@ -258,19 +258,6 @@ export default function SettingsAppearanceTab(props: {
         </SettingRow>
       </div>
 
-      <SectionHeader title={t("settings.appearance.immersiveMode")} />
-      <div className="space-y-0 divide-y divide-border rounded-lg border bg-card px-4">
-        <SettingRow
-          label={t("settings.appearance.immersiveMode")}
-          description={t("settings.appearance.immersiveMode.desc")}
-        >
-          <Toggle
-            checked={!!isImmersive}
-            onChange={() => onToggleImmersive?.()}
-          />
-        </SettingRow>
-      </div>
-
       <SectionHeader title={t("settings.appearance.customCss")} />
       <div className="space-y-2">
         <p className="text-xs text-muted-foreground">

electron/bridges/windowManager.cjs

@@ -675,6 +675,11 @@ async function createWindow(electronModule, options) {
 
   mainWindow = win;
 
+  // Clear reference when the main window is destroyed
+  win.on('closed', () => {
+    if (mainWindow === win) mainWindow = null;
+  });
+
   // Log renderer crashes for diagnostics (skip normal clean exits)
   win.webContents.on("render-process-gone", (_event, details) => {
     if (details?.reason === "clean-exit") return;
@@ -917,6 +922,7 @@ async function openSettingsWindow(electronModule, options, { showOnLoad = true }
   }
 
   const win = new BrowserWindow({
+    title: "netcatty Settings",
     width: settingsWidth,
     height: settingsHeight,
     ...(settingsX !== undefined && settingsY !== undefined ? { x: settingsX, y: settingsY } : {}),
@@ -1042,6 +1048,9 @@ async function openSettingsWindow(electronModule, options, { showOnLoad = true }
     settingsWindow = null;
   });
 
+  // Prevent HTML <title> from overriding the window title
+  win.on('page-title-updated', (e) => { e.preventDefault(); });
+
   // Load the settings page
   const settingsPath = '/#/settings';
 

electron/main.cjs

@@ -318,8 +318,8 @@ function registerAppProtocol() {
 
 function focusMainWindow() {
   try {
-    const wins = BrowserWindow.getAllWindows();
-    const win = wins && wins.length ? wins[0] : null;
+    const mainWin = getWindowManager().getMainWindow?.();
+    const win = mainWin && !mainWin.isDestroyed?.() ? mainWin : null;
     if (!win) return false;
 
     // Check if the webContents has crashed or been destroyed
@@ -1074,12 +1074,11 @@ if (!gotLock) {
       } catch {}
 
       if (focusMainWindow()) return;
-      if (BrowserWindow.getAllWindows().length === 0) {
-        void createWindow().catch((err) => {
-          console.error("[Main] Failed to create window on activate:", err);
-          showStartupError(err);
-        });
-      }
+      // Main window doesn't exist — create it even if other windows (e.g. settings) are open
+      void createWindow().catch((err) => {
+        console.error("[Main] Failed to create window on activate:", err);
+        showStartupError(err);
+      });
     });
   });