1541410 - Firefox window expands when toggling fullscreen mode on Windows

Status: RESOLVED DUPLICATE of bug 1511215

(Core :: Window Management, defect)

Description

[Ishaq Khan]

Attachment: 2.png

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:66.0) Gecko/20100101 Firefox/66.0

Steps to reproduce:

I have my Firefox windows pinned to the left of my screen using Windows snapping. Whenever I watch a video and click full screen then exit full screen the Firefox window is slightly widened.

Actual results:

The Firefox window is slightly wider by a few pixels on each side. As the window widens the left side of the window starts getting cut off bu the bounder of the monitor.

Expected results:

Whenever I exit fullscreen the window should stay the exact same size without resizing itself.

Comment 1

[Bryce Seager van Dyk [:bryce] (he/him) - Not reading bugmail]

Interesting. This does not appear specific to video.

Alternative steps to reproduce:

• Using a Windows computer open Firefox (reproed under Windows 10, doesn't repro under Linux Mint).
• Using Windows Key + Left Arrow, or Windows key + Right Arrow, snap Firefox to the left or right edge of the screen. This can also be done by dragging the Window to the edge and letting it snap.
• Rapidly move in and out of fullscreen mode using F11.

Firefox will gradually widen, this is most noticeable on the side walking off the screen, but the the other side will also grow.

Other info:

• The window does not appear to grow if it is not snapped to the side of the screen.
• Chrome does the same thing. Edge does not.
• Builds as far back as 2016-04-02 exhibit the behaviour.

Not sure what code governs this, but my best guess is layout, so moving to that component.

Comment 2

[Sean Voisen (:svoisen)]

Based on comment 1, if this is not using the fullscreen API, not specific to video, and primarily an issue on Windows then perhaps we should move this to Core::Window Management.