[X11] Fix Godot stealing focus on alternative window managers

[dsnopek]

This is taking the changes from https://github.com/Mequam/funky-godot/tree/mequam/feat/xfce4_focus_grab and turning them into a PR (as @Mequam, the original author, requested on #74378)

Unfortunately, these changes don't fix the issue I am experiencing, but since others (including the original author) wanted to see these changes as a PR, I've gone ahead and created one. :-) It's my understanding that these changes do fix some of the problems from that issue.

[bruvzg]

This looks reasonable to me (have not tested it so far). I guess it can be combined with #86671, to only grab re-focus if it's not already focused and some other window of the same app have focus (with exception for ButtonPress which should only check the current window focus).

[bruvzg]

This looks reasonable to me (have not tested it so far). I guess it can be combined with #86671, to only grab re-focus if it's not already focused and some other window of the same app have focus (with exception for ButtonPress which should only check the current window focus).

[dsnopek]

Thanks for the review!

This looks reasonable to me (have not tested it so far). I guess it can be combined with #86671, to only grab re-focus if it's not already focused and some other window of the same app have focus

Yes, I don't think the two PRs should conflict functionality-wise (there may end up being a Git conflict after one of them is merged, because of the proximity of the changed lines) although logically they are working in kind of inverse directions of each other.

Personally, when I test this PR with i3, it doesn't fix any issues for me, but it also doesn't appear to break anything.

[Calinou]

Tested locally (Fedora 39 KDE with X11, rebased against 96296e4), it works as expected.

This fixes a longstanding issue in Godot 4 where focus is stolen while the editor loads (or when a project starts), which causes some keypresses to be released if you're currently focusing on another window. I initially thought this was due to use of Window.request_attention() somewhere, but it's not – it still occurs if you make Window.request_attention() a no-op in the engine source code.

A perfect example of this is when you try to run diagonally in a game while the Godot editor loads, but one of the movement keypresses will be released after the editor is done loading. This PR fixes this issue completely. Previously, I could reproduce this pretty much every time, but I've tried 10+ times with this PR and couldn't reproduce the issue once.

I tested the editor quickly and couldn't notice any regressions in editor popup behavior.

Before

On both videos, I'm not releasing any keys while running.

simplescreenrecorder-2024-01-17_19.54.53.mp4

After (this PR)

simplescreenrecorder-2024-01-17_19.54.31.mp4

[akien-mga]

Thanks!

[YuriSizov]

Cherry-picked for 4.2.2.

[ckdarby]

@YuriSizov God's work cherry picking this commit before 4.3. Thank you!!