Titlebar fixes

ts/hooks/useIsWindowActive.ts

@@ -0,0 +1,23 @@
+// Copyright 2022 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { useEffect, useState } from 'react';
+
+export function useIsWindowActive(): boolean {
+  const { activeWindowService } = window.SignalContext;
+  const [isActive, setIsActive] = useState(activeWindowService.isActive());
+
+  useEffect(() => {
+    const update = (newIsActive: boolean): void => {
+      setIsActive(newIsActive);
+    };
+
+    activeWindowService.registerForChange(update);
+
+    return () => {
+      activeWindowService.unregisterForChange(update);
+    };
+  }, [activeWindowService]);
+
+  return isActive;
+}