2004582 - X11 + fvwm: Firefox window contents shift upward ~30px after exiting fullscreen until window is resized

Status: NEW

(Core :: Widget: Gtk, defect)

Description

[David A. Madore]

Environment:

• Linux Debian 12 (“bookworm”)
• Graphical environment: X11 (Xorg version 7.7) with fvm (2.7.0)

Steps to reproduce:

• start Firefox normally,
• enter fullscreen mode by pressing F11,
• leave fullscreen in the same way.

Results:

• entire Firefox UI is shifted upwards by ~30px (and clipped at top),
• mouse clicks are shifted by the same amount (need to click ~30px below target for effect),
• issue persists until window is resized at the WM level.

Observations:

• tested with fresh profiles,
• bug first appeared in Firefox 145,
• tested and present in versions 145, 146 and 147.

I suspect this is WM-dependent. Will run further tests if I can. Will attach screenshots shortly.

Comment 1

[David A. Madore]

Attachment: Screenshot before bug occurs

Comment 2

[David A. Madore]

Attachment: Screenshot after leaving fullscreen

Attaching screenshot of Firefox immediately after entering and leaving fullscreen mode with F11. Note how UI elements are shifted upwards (window content is shifted downwards, however?). I need to click about ~30px below target for mouse clicks to take effect.

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

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

Comment 4

[David A. Madore]

Preliminary testing suggests that:

• this is specific to fvwm2 (the bug does not occur with icewm, fluxbox or openbox),
• it is hardware-acceleration dependent, and may be specific to the (old!) Radeon HD 6450 Caicos, using the “r600” Mesa driver, card that I have,
• when hardware-acceleration is disabled, the bug affects only tooltip windows (the main UI is unaffected).

I will continue to investigate and try to post a clearer description when I can.