[Bug 1871644] Re: Top corners of Firefox windows have weird black protrusions from the rounded edges

Bug Watch Updater 1871644 at bugs.launchpad.net
Wed Apr 8 15:32:40 UTC 2020

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On 2018-11-26T18:22:11+00:00 5-greg wrote:

Created attachment 9027623

(continuing from bug 1507608)

When GL compositing is used on the Wayland backend, the GL subsurface
that actual Firefox content is rendered to does not have rounded
corners. It overdraws the parent GTK surface that contains the border
and shadow.

The Default Firefox theme actually draws the Adwaita rounded corner, but
the surface is still not transparent in the corners, so there's an ugly
gray corner.

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On 2018-12-20T11:22:25+00:00 89c51 wrote:

The same thing happens on linux also.


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On 2019-11-11T09:37:46+00:00 Stransky wrote:

I'm not sure how to fix that on Wayland as it does not support XShape
mask which we use on X11.

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On 2019-11-11T20:02:34+00:00 5-greg wrote:

huh, the corners were just masked out? But who draws the non-transparent
gray pixels there in the first place?

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On 2020-01-16T12:34:54+00:00 Jan Steffens wrote:

Created attachment 9121264
Default and Light theme corners, GNOME Shell window screenshots, scale 2, on striped background

This almost works for me, and the behavior is the same whether basic
layers or WR is used.

As I understand, the way CSD works here is that the window uses a GTK
window style which only draws the shadow around an inner widget drawn by
Firefox. Adwaita gives us a soft shadow and a 1px semitransparent

The Default theme has a slight glitch where the corners are not as
transparent as they should be. I think the tab bar's "headerbar" styling
is trying to draw a window shadow here which gets overlaid with the
shadow drawn by the window. We need to either somehow remove the shadow
from the headerbar style applied to the tab bar, or somehow mask out the
drawing of the window shadow so that it only draws outside the inner

The Light and Dark themes have no "headerbar" styling, so the tab bar
has sharp corners which clash with the rounded outline from the window's
Adwaita theme.

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On 2020-03-16T21:04:38+00:00 Limpid-mazarine wrote:

Hi, the issue still exists on Firefox 74.0 on Fedora (Wayland). Any idea
how to fix this?

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** Changed in: firefox
       Status: Unknown => New

** Changed in: firefox
   Importance: Unknown => Medium

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