What still shows after you hide a window

Marking a window as excluded from capture covers that window. It does not make your screen private, and any tool that implies otherwise is overselling itself.

Five things still reach viewers on Windows. We hit each of them during testing rather than reading about them, and none is fixable by the application — four are properties of the operating system and one is physics. Here is each, why it happens, and what actually works against it.

1. Notification banners

A message arrives, Windows slides a banner into the corner, and it is captured like anything else on screen. Protecting the chat application does not cover it, because the banner is a different window — owned by the notification system, not by the app.

What works: turn off notifications for the duration.

• Windows 11: Settings → System → Notifications → turn on Do not disturb.
• Windows 10: Settings → System → Focus assist → set to Alarms only.

Both have a shortcut worth learning: open the notification centre and toggle it there, so you can do it after a call has already started.

The limit of that fix: it catches the standard Windows banners, which is the great majority. Some applications draw their own pop-up windows that never go through the notification system, and those are unaffected. If one of those apps is genuinely sensitive, close it rather than trusting a setting.

2. Task View, Alt-Tab and taskbar previews

This is the one that surprises people, and it is the one we would most like to fix.

Press Alt-Tab, or open Task View, or hover a taskbar icon, and Windows shows a live thumbnail of every window — including the protected one, with its real content. Those thumbnails are drawn by Windows itself, outside any application’s reach, and the capture flag does not extend to them.

What works: a habit. Do not open Task View or Alt-Tab while you are presenting. Switch windows by clicking the taskbar icon directly, or with Win+1, Win+2 and so on, which raise a window without drawing a preview of everything else.

This is not going to be fixed in a future version, and saying otherwise would be dishonest. It is a property of the operating system.

3. The moment before you protect

Protection applies the instant you set it, which also means it does not apply retroactively to a window that has been on screen for the last ten seconds.

The realistic failure is not technical: you start sharing, then remember. Whatever was visible in that gap was visible.

What works: protect before you share, and learn Ctrl+Shift+Q, which protects whichever window you are working in from any application without switching apps. Setting protection up before a call is worth more than any recovery afterwards.

4. Sharing the window itself

Every meeting app offers to share a single window rather than the whole screen. If you share the protected window itself, Windows hands that window’s own pixels straight to the meeting app. Nothing can get in between, because there is no screen capture to exclude anything from.

What works: share your entire screen when you need protection, or share a different single window — which is inherently safe, since nothing else is captured at all.

5. Anything pointed at the glass

A capture card on the HDMI output, a phone camera, or someone stood behind you reads the monitor itself. Software operates above the glass; none of this reaches below it.

What works: nothing software can do. Worth stating because it defines the boundary of what any tool in this category can promise.

What this leaves

The case that actually causes the damage — a private window sitting open on the shared screen, for the whole call, in front of everyone — is covered, and it is covered without closing the window or moving it somewhere you cannot read it.

The five above are brief, mostly avoidable by habit, and several are outside what software can reach at all. The useful thing is knowing which is which, so you are relying on the tool where it is strong and on your own habits where it is not.

The check that settles it

Whatever you use, verify on someone else’s screen rather than your own:

1. Start a meeting alone and join it from your phone.
2. Protect a window, then share your entire screen.
3. Look at the phone — not at the meeting app’s self-preview, and not at a screenshot of your own desktop. Both are generated on the machine that already knows the answer you want.
4. While you are there, open Task View and watch what the phone shows. That is the leak in point 2, and seeing it once is worth more than reading about it.

Hushglass protects a chosen window from screen-share viewers only, free for one window, on Windows 10 version 2004 or later. Everything on this page is what it does not do, written down in the same place as what it does.