Hiding an Electron window from screen share: 4 things setContentProtection doesn't tell you

Evyn John — Thu, 12 Nov 2026 22:11:34 +0000

Natively is a desktop AI assistant for meetings and interviews. It listens to the call, transcribes it, and shows answers and notes in a small overlay. People use it while they share their screen, so the overlay has an obvious requirement: when the user turns on Undetectable mode, the overlay must not appear in the share or the recording.

Electron gives you one line for this:

win.setContentProtection(true);

On macOS it sets the window's sharingType to NSWindowSharingNone. On Windows it calls SetWindowDisplayAffinity with WDA_EXCLUDEFROMCAPTURE (Windows 10 2004 and later). That line gets you most of the way. Here is what it took to get the rest, from code that ships in Natively today.

1. Apply it to every window, not just the one you think of

An "overlay" in a real app is several windows: the answer panel, a pill, a toggle, a popover catcher, sometimes a launcher. If one of them is missed, that one shows up in the share.

We keep a single method that walks every live window and pushes the same value:

private applyContentProtection(enable: boolean): void {
  const windows = [
    this.launcherWindow,
    this.overlayWindow,
    this.pillWindow,
    this.toggleWindow,
    this.popoverCatcher,
  ];
  windows.forEach((win) => {
    if (win && !win.isDestroyed()) win.setContentProtection(enable);
  });
}

Any window created later (settings, model picker, screenshot cropper) reads the current state when it is created, so a window opened mid-meeting doesn't slip through.

2. Dedupe the calls on Windows

Our setter was called from several places: the settings toggle, every overlay show, and a workaround around Win+Tab. On Windows, setting the same display affinity again and again churns DWM, and the window can go black or blank for a few hundred milliseconds. So the public setter does nothing when the value hasn't changed:

public setContentProtection(enable: boolean): void {
  if (this.contentProtection === enable) return;
  this.contentProtection = enable;
  this.applyContentProtection(enable);
}

3. On macOS, re-assert after you touch the Dock

This one cost us the most time. Undetectable mode also hides the app from the Dock with app.dock.hide(). That flips the app's activation policy, and WindowServer re-evaluates every window. It can quietly reset sharingType to the default, which means the overlay is visible in the share again. Your in-memory flag still says true, so the deduped setter above would skip the call.

The fix is a second method that skips the dedupe and pushes the current value to the OS again:

public reassertContentProtection(): void {
  this.applyContentProtection(this.contentProtection);
}

Call it after every app.dock.hide() / app.dock.show().

4. Windows has a taskbar, and the taskbar is not the window

On macOS, hiding from the Dock removes the app's visible presence. On Windows, a window that is excluded from capture can still have a taskbar button with the app's name on it, and the taskbar is part of a full-screen share. Most of our windows are created with skipTaskbar: true. The launcher is the exception because in normal mode it is the main window, so we sync it with the mode:

public syncLauncherTaskbarForStealth(): void {
  if (process.platform !== 'win32') return;
  this.launcherWindow?.setSkipTaskbar(!!this.appState.getUndetectable());
}

The macOS path doesn't use this at all. Forcing skipTaskbar there would change behaviour on a platform that handles it through the Dock.

Test the capture paths you actually care about

Content protection is a request to the OS compositor, and different capture APIs respect it differently. Modern APIs (ScreenCaptureKit on macOS, Windows Graphics Capture) honour it. Some older capture paths may not. So we test with the apps people really share from (Zoom, Google Meet in Chrome, Teams, OBS, the system screenshot tool) on both platforms, with the mode on and off, and we treat "it was hidden on my machine" as one data point, not proof.

Where this lives

All of this is in Natively's source on GitHub: Natively-AI-assistant/natively-cluely-ai-assistant, in electron/WindowHelper.ts. Natively runs on macOS and Windows and is free for personal use. You can bring your own AI keys or run models locally with Ollama. If you're building something with an always-on-top overlay, I hope this saves you an afternoon.

Download and docs: heynatively.com

DEV Community: Evyn John