1865215 - Linux only: dragged CSS styled element loses focus

Status: UNCONFIRMED

(Core :: DOM: UI Events & Focus Handling, defect)

Description

[yavorbu]

Attachment: ff-css-bug.gif

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/119.0

Steps to reproduce:

Probably on any site.
Just drag any "on mouse over" styled element. It will revert back to non hovered and loose focus.
I have tested this on 119.0.1 (Arch linux), 116.0.2 (Ubuntu 22.04.3 Live ISO)
I hope the attached gif-s describe it better.

Actual results:

The element losses focus.
This is particularly bad if the element is in Firefox side-bar. For example a tab in "Tree Style Tab" or "Sidebery" extensions. With custom userChrome.css to auto-hide the side-bar the whole side-bar looses focus and auto-hide itself!

Expected results:

The initial focus should be retained after drag starts.
This is problem only on Linux. G-Chrome and chromium, Fifrefox on Windows behave the same to each other. The same userChrome.css works just fine on Windows, no auto-hide stuff when dragging tabs around.

Comment 1

[yavorbu]

Attachment: chromium.gif

How the same looks in Chromium

Comment 2

[yavorbu]

Attachment: userChrome.css

Just for completion.

Comment 3

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

The Bugbug bot thinks this bug should belong to the 'Core::DOM: UI Events & Focus Handling' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 4

[Andrew McCreight [:mccr8]]

Henri, do you have any idea why we might be losing focus here only on Linux? Where should a bug like this go? Thanks.

The Wikipedia example doesn't seem that bad, but it sounds like the behavior causes big issues for Tree Style Tab.

Comment 5

[Henri Sivonen (:hsivonen)]

(In reply to Andrew McCreight [:mccr8] from comment #4)

Henri, do you have any idea why we might be losing focus here only on Linux?

I don't know, sorry.

Where should a bug like this go? Thanks.

Without knowing the root cause, it's unclear if this belongs in this component or in the Gtk widget (given the noted difference on Windows).