diff --git a/apps/client/src/common/components/navigation-menu/NavigationMenu.tsx b/apps/client/src/common/components/navigation-menu/NavigationMenu.tsx
index 765cfc2ef4..6b64898943 100644
--- a/apps/client/src/common/components/navigation-menu/NavigationMenu.tsx
+++ b/apps/client/src/common/components/navigation-menu/NavigationMenu.tsx
@@ -1,13 +1,14 @@
 import { Dialog } from '@base-ui/react/dialog';
-import { useDisclosure, useFullscreen } from '@mantine/hooks';
+import { useDisclosure } from '@mantine/hooks';
 import { memo } from 'react';
 import { IoClose, IoContract, IoExpand, IoLockClosedOutline, IoSwapVertical } from 'react-icons/io5';
 import { LuCoffee } from 'react-icons/lu';
 import { useLocation } from 'react-router';
 
-import { isLocalhost, supportsFullscreen } from '../../../externals';
+import { isLocalhost } from '../../../externals';
 import { canUseWakeLock, useKeepAwakeOptions } from '../../../features/keep-awake/useWakeLock';
 import { navigatorConstants } from '../../../viewerConfig';
+import { useFullscreen } from '../../hooks/useFullscreen';
 import { useIsSmallScreen } from '../../hooks/useIsSmallScreen';
 import { useClientStore } from '../../stores/clientStore';
 import { useViewOptionsStore } from '../../stores/viewOptions';
@@ -32,7 +33,7 @@ function NavigationMenu({ isOpen, onClose }: NavigationMenuProps) {
   const isSmallScreen = useIsSmallScreen();
 
   const [isRenameOpen, handlers] = useDisclosure(false);
-  const { fullscreen, toggle } = useFullscreen();
+  const { fullscreen, isSupported: isFullscreenSupported, toggle: toggleFullscreen } = useFullscreen();
   const { mirror, toggleMirror } = useViewOptionsStore();
   const { keepAwake, toggleKeepAwake } = useKeepAwakeOptions();
   const location = useLocation();
@@ -57,8 +58,14 @@ function NavigationMenu({ isOpen, onClose }: NavigationMenuProps) {
             </IconButton>
           </div>
           <div className={style.body}>
-            {supportsFullscreen && (
-              <NavigationMenuItem active={fullscreen} onClick={toggle}>
+            {isFullscreenSupported && (
+              <NavigationMenuItem
+                active={fullscreen}
+                onClick={() => {
+                  onClose();
+                  toggleFullscreen();
+                }}
+              >
                 Toggle Fullscreen
                 {fullscreen ? <IoContract /> : <IoExpand />}
               </NavigationMenuItem>
diff --git a/apps/client/src/common/hooks/useFullscreen.ts b/apps/client/src/common/hooks/useFullscreen.ts
new file mode 100644
index 0000000000..390502f7b0
--- /dev/null
+++ b/apps/client/src/common/hooks/useFullscreen.ts
@@ -0,0 +1,60 @@
+import { useCallback, useEffect, useState } from 'react';
+
+interface UseFullscreenReturn {
+  /** Whether the document is currently in fullscreen mode */
+  fullscreen: boolean;
+  /**
+   * Whether the Fullscreen API is available and permitted in the current browsing context.
+   * When false, `toggle` is a no-op and the UI should hide or disable the action.
+   */
+  isSupported: boolean;
+  /**
+   * Toggles fullscreen on/off.
+   * Safe to use directly as an onClick handler — the underlying Promise is handled
+   * internally, so rejections (eg. browser policy, user denial) never surface as
+   * unhandled promise rejections.
+   */
+  toggle: () => void;
+}
+
+/**
+ * Manages browser fullscreen state.
+ *
+ * Compared to @mantine/hooks useFullscreen:
+ * - `isSupported` is co-located so there is a single source of truth
+ * - `toggle` is a plain void callback, safe to pass directly to event handlers
+ * - Error handling is internal; callers do not need try/catch
+ * - Only targets document.documentElement (the ref API is not used in this project)
+ * - No vendor-prefix shims (all supported browsers implement the standard API)
+ */
+export function useFullscreen(): UseFullscreenReturn {
+  const isSupported = Boolean(document.fullscreenEnabled);
+  const [fullscreen, setFullscreen] = useState(Boolean(document.fullscreenElement));
+
+  // Keep `fullscreen` state in sync with the actual browser state.
+  // The fullscreenchange event fires whenever the document enters or exits fullscreen
+  // (including when the user presses Escape to exit), so React state never drifts
+  // from reality. The listener is removed on unmount via the cleanup return.
+  useEffect(() => {
+    const handleChange = () => setFullscreen(Boolean(document.fullscreenElement));
+    document.addEventListener('fullscreenchange', handleChange);
+    return () => document.removeEventListener('fullscreenchange', handleChange);
+  }, []);
+
+  const toggle = useCallback(() => {
+    if (!isSupported) return;
+
+    if (!document.fullscreenElement) {
+      document.documentElement.requestFullscreen().catch(() => {
+        // requestFullscreen() can be rejected in certain browser contexts
+        // (eg. browser security policy, extensions blocking fullscreen)
+      });
+    } else {
+      document.exitFullscreen().catch(() => {
+        // exitFullscreen() can also be rejected in rare edge cases
+      });
+    }
+  }, [isSupported]);
+
+  return { fullscreen, isSupported, toggle };
+}
diff --git a/apps/client/src/externals.ts b/apps/client/src/externals.ts
index 0393d65360..b9c38edfa1 100644
--- a/apps/client/src/externals.ts
+++ b/apps/client/src/externals.ts
@@ -27,7 +27,6 @@ export const isLocalhost = currentHostName === 'localhost' || currentHostName ==
 export const isOntimeCloud = document.querySelector('base')?.hasAttribute('data-is-cloud');
 
 export const isTouchDevice = 'ontouchstart' in window || navigator.maxTouchPoints > 0;
-export const supportsFullscreen = document.fullscreenEnabled;
 
 // resolve entrypoint URLs