[bug] ```document.exitFullscreen``` will cause Tauri to exit fullscreen mode

[felix869218536]

Describe the bug

When launching a Tauri full screen application, if there is an element in the webview that uses requestFullscreen for full screen, calling document.exitFullscreen will cause Tauri to exit full screen

Reproduction

No response

Expected behavior

No response

Full tauri info output

$ cargo tauri info

[✔] Environment
    - OS: Windows 10.0.22631 x86_64 (X64)
    ✔ WebView2: 140.0.3485.94
    ✔ MSVC: Visual Studio Community 2022
    ✔ rustc: 1.89.0 (29483883e 2025-08-04)
    ✔ cargo: 1.89.0 (c24e10642 2025-06-23)
    ✔ rustup: 1.28.2 (e4f3ad6f8 2025-04-28)
    ✔ Rust toolchain: stable-x86_64-pc-windows-msvc (overridden by environment variable RUSTUP_TOOLCHAIN)
    - node: 22.12.0
    - pnpm: 10.13.1
    - yarn: 1.22.22
    - npm: 10.9.0
    - bun: 1.2.18

[-] Packages
    - tauri 🦀: 2.8.4, (outdated, latest: 2.8.5)
    - tauri-build 🦀: 2.4.0, (outdated, latest: 2.4.1)
    - wry 🦀: 0.53.2, (outdated, latest: 0.53.3)
    - tao 🦀: 0.34.2, (outdated, latest: 0.34.3)
    - tauri-cli 🦀: 2.4.1 (outdated, latest: 2.8.4)

[-] Plugins
    - tauri-plugin-clipboard-manager 🦀: 2.3.0
    - tauri-plugin-autostart 🦀: 2.5.0
    - tauri-plugin-log 🦀: 2.6.0, (outdated, latest: 2.7.0)
    - tauri-plugin-opener 🦀: 2.2.3, (outdated, latest: 2.5.0)
    - tauri-plugin-localhost 🦀: 2.3.0
    - tauri-plugin-notification 🦀: 2.3.1
    - tauri-plugin-http 🦀: 2.5.2
    - tauri-plugin-fs 🦀: 2.4.2
    - tauri-plugin-single-instance 🦀: 2.3.3, (outdated, latest: 2.3.4)
    - tauri-plugin-os 🦀: 2.3.1
    - tauri-plugin-persisted-scope 🦀: 2.3.2
    - tauri-plugin-store 🦀: 2.4.0
    - tauri-plugin-dialog 🦀: 2.3.3, (outdated, latest: 2.4.0)
    - tauri-plugin-shell 🦀: 2.3.1

[-] App
    - build-type: bundle
    - CSP: default-src 'self' ipc: asset: http: https: data: blob:; style-src 'self' 'unsafe-inline' 'unsafe-eval' blob: http: https:; script-src 'self' 'unsafe-inline' 'unsafe-eval' blob: http: https:; connect-src 'self' ipc: http: https: ws: wss: mqtt: mqtts: rtsp: rtmp:
    - frontendDist: ./ui

Stack trace

Additional context

No response

[FabianLars]

This is somewhat of a consequence of #13558 (before this you couldn't toggle actual fullscreen). Sounds like we have to keep track of the state before element fullscreen so we can restore back to it.

[Legend-Master]

To me I feel like, if you don't want this to happen, override it with an init script document.exitFullscreen = () => {} makes more sense then having tauri disable that by default

[FabianLars]

ah if that works then i can live with that as well.

[BlueManCZ]

Hello,

I believe this issue should be reopened because the core problem persists, and the suggested workaround does not prevent the window exit in a critical use case. In fact, calling document.exitFullscreen() does not exit fullscreen in my case, so I don't need to override it.

I am developing a kiosk application set to start in OS-level fullscreen via tauri.conf.json. This application runs on a Windows machine with touch-only display. I have a native video element there that can be set to fullscreen via the native video player's built-in button. Clicking the button again to exit fullscreen exits the fullscreen, and the entire Tauri application window exits OS fullscreen (breaking the kiosk mode).

I think the problem originates from a deep-level signal triggered by the browser's proprietary video controls. It looks like the native webview controls are initiating an underlying event that incorrectly signals the OS layer to exit the Tauri window's native fullscreen state. Can this be an internal webview/Tauri hook issue, not a standard JavaScript Fullscreen API problem?

Is there something I can do to prevent this from happening?

The only way i found to maintain the kiosk lock is to immediately re-enforce the fullscreen state upon detecting the exit event, which is a state-forcing loop and causes a minor visual flicker:

// The current necessary workaround to prevent kiosk exit
document.addEventListener('fullscreenchange', async () => {
  if (!document.fullscreenElement) {
    const isAppFullscreen = await getCurrentWindow().isFullscreen();
    if (!isAppFullscreen) {
      // Force the Tauri window back into OS fullscreen
      await getCurrentWindow().setFullscreen(true);
    }
  }
});

[Legend-Master]

@BlueManCZ Preventing the fullscreen API/browser fullscreen from actually going/existing fullscreen in this case sounds reasonable, I think maybe you could open a new feature request issue for this, no promise on when will this be worked on though (an API that toggles this behavior or on handler hook)