2028773 - Backrounded Firefox window with middle click USB open flickers when closed

Status: NEW

(Firefox :: Address Bar, defect, P3)

Description

[Adrian Florinescu [:aflorinescu]]

Attachment: flicker-close.mp4

Found in

• 150.0b4

Affected versions

• 151.0a1 (2026-04-01)
• 150.0b4

Tested platforms

• Affected platforms: Windows 11, Windows 10
• Unaffected platforms: Mac 13, Ubuntu 24.04

Steps to reproduce

1. Type a string into address bar
2. Open USB.
3. Middle click(ctrl+click) on any of the engine items in the USB, for example duckduckgo
4. Without minimizing Fx, overlay another window on top of Fx
5. Right-click the Firefox taskbar icon and select close window

Expected result
Firefox is closed.

Actual result
A flicker like event is happening before Firefox is closed, bringing the Firefox window to the foreground before closing. (see attached video)

Regression range

• A regression range cannot be confirmed, but my assumption is that becuse bug 2025746, the USB panel remains open and when trying to close Firefox window, it forces Firefox to foreground focus before closing.

Note
Uncertain on which component this bug should be filled under, so starting with window management.

Comment 1

[BugBot [:suhaib / :marco]]

:dao, since you are the author of the regressor, bug 2025746, could you take a look? Also, could you set the severity field?

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