Closed Bug 2037206 Opened 4 months ago Closed 1 month ago

[KDE/Wayland] userChrome.css transparent backgrounds render opaque in Firefox 150

Categories

(Core :: Widget: Gtk, defect)

Product:
Core
Component:
Widget: Gtk
Version:
Firefox 150
Type:
defect

Tracking

()

Status:
RESOLVED INVALID

People

(Reporter: mozilla.saturday612, Unassigned)

References

(Regression)

Details

(Keywords: regression)

Steps to reproduce:

Environment:
OS: EndeavourOS (Arch-based)
Desktop: KDE Plasma 6, Wayland (KWin compositor)
GPU: NVIDIA RTX 4090, driver [your driver version]
Firefox: 150.0.1-1 (regression), 149.0-1 (working)

Steps to reproduce:

  1. Set widget.transparent-windows = true in about:config
  2. Set toolkit.legacyUserProfileCustomizations.stylesheets = true
  3. Add background: transparent !important to toolbar elements in userChrome.css
  4. Restart Firefox

Regression:
Works in Firefox 149.0-1, broken in 150.0.1-1. Downgrading to 149 immediately resolves it. Other userChrome rules (colors, layout changes) continue working in 150 — only transparency is affected.

Notes:
Firefox 150 release notes mention a Wayland compositor fix for Cosmic compositor. Suspected cause: opaque region reporting change breaking ARGB visual transparency on KWin.

Actual results:

Toolbar renders fully opaque, no transparency visible

Expected results:

Toolbar background is transparent, KWin blur composites through

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.

Component: Untriaged → Widget: Gtk
Product: Firefox → Core

Can you please use mozregression to find broken commit?
https://fedoraproject.org/wiki/How_to_debug_Firefox_problems#Use_Mozregression_tool
Thanks.

Flags: needinfo?(mozilla.saturday612)

(In reply to Martin Stránský [:stransky] (ni? me) from comment #2)

Can you please use mozregression to find broken commit?
https://fedoraproject.org/wiki/How_to_debug_Firefox_problems#Use_Mozregression_tool
Thanks.

https://hg-edge.mozilla.org/integration/autoland/pushloghtml?fromchange=c652bb4f7aa58ff9a36d67390a64f0495381c66d&tochange=8d54cc2c66e9d90b6f297c017c6294c3c6b30edd

Flags: needinfo?(mozilla.saturday612)

Thanks, adding as regression but I don't think we support such setup so I guess it's WONTFIX. But let's see what Emilio says.

Keywords: regression
Regressed by: 2005854

You need to make the <body> transparent now, see bug 2048355.

Status: UNCONFIRMED → RESOLVED
Closed: 1 month ago
Resolution: --- → INVALID
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