1781262 - [xwayland] Window borders have a 9px wide deadzone beyond resize area which doesn't allowing clicking through to windows beneath

Status: NEW

(Core :: Widget: Gtk, defect, P3)

Description

[Kestrel]

Attachment: Video showing cursor not changing over text areas near edge of window

STR:

1. Start with MOZ_ENABLE_WAYLAND=0 on Ubuntu 22.04 (Wayland).
2. Position a text document window beneath the Firefox window.
3. Move the cursor near the edges of the Firefox window, just beyond the resize area, over the text document.

Expected:
Cursor icon changes over text areas and clicking brings below window into focus.

Actual:
Cursor icon doesn't change within 9px wide deadzone and clicking does nothing. Does not happen with Wayland or X11, only XWayland.

Regression window:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=d1eb6fe5a1fa5457425c5a33f212516a5eeaa381&tochange=498e0e6f9b19107c8c17525a3d01a659f89002e8

Regressed by Bug 1756903.

Comment 1

[Robert Mader [:rmader]]

This is likely not really a regression as the bug was probably already present on all DEs that used CSD before bug 1756903. It just affects Gnome as well now.

@Kestrel: does the issue also appear if you log into a native Xorg session? Just so we know whether it might be a Xwayland issue.

Comment 2

[Kestrel]

It does not appear when logging in with "Ubuntu on Xorg" (X11), only with XWayland.

Comment 3

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

:emilio, since you are the author of the regressor, bug 1756903, could you take a look?
For more information, please visit auto_nag documentation.

Comment 4

[Emilio Cobos Álvarez (:emilio)]

I don't think this is too worrying given comment 2 and that this is GNOME-only... Ideally we'd get Wayland shipping sooner rather than later instead.

Comment 6

[Kestrel]

Workarounds include enabling native Wayland with MOZ_ENABLE_WAYLAND=1, enabling the title bar or setting MOZ_GTK_TITLEBAR_DECORATION=system.