1818517 - Dragging content removes element hover state on Linux

Status: REOPENED

(Core :: Widget: Gtk, defect)

Description

[MrOtherGuy]

STR:

1. Go to https://yari-demos.prod.mdn.mozit.cloud/en-US/docs/Web/CSS/:hover/_sample_.basic_example.html
2. Move cursor over the light-blue box containing a link
3. The box becomes orange because it has :hover styling
4. Start dragging the link

Expected:

The box stays orange for as long as the link is being dragged regardless of where the cursor is

Actual:

The box loses its :hover styling immediately when the dragging starts.

I was able to use mozregressions to trace the problem to bug 1798131

It seems that bug 1798131 changed the behavior on Linux such that starting a drag-sessions always removes hover-state from elements. On Windows, and on Linux before bug 1798131 the behavior is such that the hover state stays "locked" for as long as a drag-session is in progress.

This could potentially make so UI widgets unusable, for example if there is some panel-like list which is shown only when hovering over a trigger and there are items inside the panel which can be re-ordered by dragging them.

Comment 1

[MrOtherGuy]

For what it's worth, I've found that toggling widget.gtk.ignore-bogus-leave-notify to 1 solves this issue - however I cannot say if doing that causes some other problems, but nothing immediately obvious at least.

From about:support:

Window Protocol:     wayland
Desktop Environment: gnome

Comment 2

[Emilio Cobos Álvarez [:emilio]]

FWIW I can't reproduce the same issue on Plasma Wayland (but I can on GNOME)...

Comment 3

[Emilio Cobos Álvarez [:emilio]]

Attachment: Bug 1818517 - Ignore crossing-due-to-grab-start events. r=stransky

An alternative for this could be to just ignore leave-notify during a
drag, but that seemed a bit more hackish.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/8e7588542175
Ignore crossing-due-to-grab-start events. r=stransky

Comment 5

[Noemi Erli[:noemi_erli]]

https://hg.mozilla.org/mozilla-central/rev/8e7588542175

Comment 6

[Norisz Fay [:noriszfay]]

Backed out as requested by dev for causing Bug 1827446
Backout link

Comment 7

[Pascal Chevrel:pascalc]

Backed out changeset 8e7588542175 (Bug 1818517) for causing Bug 1827446
https://hg.mozilla.org/releases/mozilla-beta/rev/745a75b1da94

Comment 8

[Emilio Cobos Álvarez [:emilio]]

What's the ni? above about?

Comment 9

[Suhaib Mujahid [:suhaib]]

(In reply to Emilio Cobos Álvarez (:emilio) from comment #8)

What's the ni? above about?

The following is the comment (similar to https://bugzilla.mozilla.org/show_bug.cgi?id=1828020#c2 -- I will follow up on why it is not posted in the case of this bug):

There is an r+ patch which didn't land and no activity in this bug for 2 weeks.
:emilio, could you have a look please?
If you still have some work to do, you can add an action "Plan Changes" in Phabricator.