Bug 501467

Summary:	Firefox windows are very small when starting the app
Product:	[Plasma] kwin	Reporter:	TraceyC <kdedev>
Component:	general	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	CONFIRMED ---
Severity:	normal	CC:	john.kizer, nate
Priority:	NOR	Keywords:	wayland-only
Version First Reported In:	git master
Target Milestone:	---
Platform:	Solus
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	Firefox windows after initial launch where two are very small

Description TraceyC 2025-03-13 20:33:45 UTC

Created attachment 179378 [details]
Firefox windows after initial launch where two are very small

SUMMARY
When starting Firefox, the remembered windows are re-opened but are very small. Also, when opening a new window (Ctrl + n), it appears as a normally sized window for a brief second, and then goes down to a very small size.

STEPS TO REPRODUCE
Set Firefox that on Startup "Open previous windows and tabs"
1. Open Firefox, and open a second window. Have different tabs in them.
2. Close and re-open Firefox. Then open a new Firefox window

OBSERVED RESULT
Some restored windows are very small. A new window is also very small.

EXPECTED RESULT
Windows that are re-opened from the last session have the same size. New windows have whatever the default Firefox window size is

SOFTWARE/OS VERSIONS
Operating System: Solus 4.7
KDE Plasma Version: 6.3.80
KDE Frameworks Version: 6.13.0
Qt Version: 6.8.2
Kernel Version: 6.12.17-314.current (64-bit)
Graphics Platform: Wayland
Processors: 16 × 11th Gen Intel® Core™ i7-11800H @ 2.30GHz
Memory: 64 GiB of RAM (62.5 GiB usable)
Graphics Processor 1: Intel® UHD Graphics
Graphics Processor 2: NVIDIA GeForce RTX 3060 Laptop GPU
Manufacturer: Dell Inc.
Product Name: XPS 17 9710

ADDITIONAL INFORMATION
This happens with a regular Firefox profile as well as a profile that has no addons and default settings
This started with Plasma 6.3.3
It isn't happening on another system with git-master on Solus, so I suspect something in the rc files. I'll test with a new user and on X11

There is one report of the same issue on the forums from May
https://discuss.kde.org/t/since-the-update-to-plasma-6-firefox-only-starts-in-a-small-window/16297

Comment 1 TraceyC 2025-03-13 21:29:05 UTC

I did get it to reproduce on the other machine as well, with git-master Wayland
I had to exit and restart Firefox two or three times before one of the windows was restored to a very small size. After that, the bug repeatedly happened

I can reproduce with 
- Another user that was only a few days old and has next to no configuration, and is relatively new
- Single or multiple screens

I wasn't able to reproduce with
- git-master X11
- a brand new user

Renaming these under an affected user had no effect:
~/.config/kwinrulesrc
~/.config/kwinrc
~/.config/kwinoutputconfig.json
~/.cache/kwin/

Comment 2 Nate Graham 2025-03-14 15:46:31 UTC

FWIW I saw this once recently with LibreWolf, but was not able to find a way to reproduce it.

Comment 3 John Kizer 2025-03-27 19:06:41 UTC

Maybe a long-shot question, but, does the issue still occur if you set Firefox to use a system-provided Title Bar (if I understand it right, server-side decorations rather than client-side)?

Comment 4 TraceyC 2025-04-04 21:15:42 UTC

From a brief web

Comment 5 TraceyC 2025-04-04 21:18:48 UTC

From a brief web search, it seems the way to do this is with MOZ_GTK_TITLEBAR_DECORATION

That hadn't been set, so I tried adding it and setting it to "server". I'll try to reproduce.

Comment 6 TraceyC 2025-04-04 21:26:46 UTC

That eliminated the title bar, so it must not be the right value. The variable wasn't present anymore when I re-opened the browser
I had to re-enable the title back through customize toolbar - check Title Bar
This apparently correlates to about:config 'Tabs in Titlebar" being default (value of 2) - bug is present as well

Now all the windows that are restored start out tiny