2055201 - Picture in Picture no longer hides the Windows Taskbar

Status: RESOLVED DUPLICATE of bug 2048501

(Core :: Widget: Win32, defect)

Description

[4am]

Attachment: Screenshot 2026-07-15 081613 - bottom of fullscreen window hidden.png

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:152.0) Gecko/20100101 Firefox/152.0

Steps to reproduce:

1. Open any website, use F11 to Fullscreen the tab
2. Switch to another tab with a video player (doesn't seem to matter which site), pop out the video player into a Picture-in-Picture dialog

Actual results:

The presence of the PiP dialog prevents the Windows Taskbar from hiding. This blocks elements of the fullscreened browser window from being visible on the screen. (This may be related to 2042533?)

Expected results:

when the PiP dialog is not in fullscreen mode Windows Taskbar should be hidden based on the highest browser window's state to prevent the windows Taskbar from hiding elements of the page in the fullscreened browser window. I would also expect Taskbar visibility to change when selecting a different browser window on the same screen that is not in fullscreen mode. Essentially, the PiP dialog should not touch the Taskbar state unless it has been fullscreened itself.

Comment 1

[BugBot [:suhaib / :marco]]

The Bugbug bot thinks this bug should belong to the 'Toolkit::Picture-in-Picture' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[4am]

I just realized I did not specify Windows or Firefox versions, apologies:

Windows 11 Pro 25H2 Build 26200.8875 with Windows Feature Experience Pack 1000.26100.334.0
Firefox 152.0.6

Tested with and without Add-Ons enabled

Comment 3

[kpatenio]

Thanks for the bug report. Moving this ticket over to Core :: Widget: Win32 since the folks there may have a better idea of what's going on.

Comment 5

[Jan Brasna [:janbrasna]]

This should be fixed in 154beta if you could help verify using beta.mozilla.org or nightly.mozilla.org on the affected system. Thanks!

Comment 6

[4am]

I can verify that the issue is fixed, but I've found a possible regression: Switching to a **standard **browser window that is not in fullscreen mode now does not reveal the task bar; the fullscreen window keep the Taskbar hidden. Maximizing (note: not to be confused with fullscreening) the standard window works, and it continues to respect the Taskbar boundary, but in the moveable state it can be moved to the bottom of the screen as if the Taskbar is still hidden.

This worked as expected in 153

Comment 7

[David Parks [:handyman]]

Filed bug 2064173.