Bug 435181

Summary:	Keyboard shortcuts which include the shortcut for changing keyboard layout in themselves are not dispatched to applications
Product:	[Plasma] kwin	Reporter:	Lyubomir <liubomirwm>
Component:	input	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UPSTREAM
Severity:	normal	CC:	butirsky
Priority:	NOR
Version First Reported In:	5.18.5
Target Milestone:	---
Platform:	Other
OS:	Linux
See Also:	https://bugs.kde.org/show_bug.cgi?id=435187
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Lyubomir 2021-03-31 11:23:22 UTC

SUMMARY
When for example you use/have set Alt + Shift to change the keyboard layout in KDE Plasma, using Alt + Shift + RightArrow for example is not delivered to Visual Studio Code and the expand selection feature doesn't work. If you change the keyboard layout change combination in KDE, then it starts to work in Visual Studio Code. Presumably it is the same for Ctrl + Shift when it is used for keyboard layout change - then for example Ctrl + Shift + T would not restore the last closed tab in Firefox.

This creates unnecessary problems, which for example work okay in Windows. If it can work well in Windows simultaneously for changing the keyboard layout and for keyboard combinations in other apps (being delivered to them), it should be able to function okay also in KDE.

I believe it is bug https://gitlab.freedesktop.org/xorg/xserver/-/issues/258#note_859337, which according to the discussion seems would not be fixed by X.Org and would need to be fixed by each Desktop Environment.

STEPS TO REPRODUCE
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OBSERVED RESULT
Keyboard shortcuts which include in themselves the shortcut for changing keyboard layout are not successfully delivered to applications.

EXPECTED RESULT
We should be able to both use Alt + Shift for changing keyboard language and Alt + Shift + RightArrow for Expand Selection in Visual Studio Code, as these are two different shortcuts and certainly there is difference between them.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Kubuntu 20.04.2
KDE Plasma Version: 5.18.5
KDE Frameworks Version: 5.68.0
Qt Version: 5.12.8

Comment 1 Andrey 2021-03-31 13:04:45 UTC

"according to the discussion seems would not be fixed by X.Org and would need to be fixed by each Desktop Environment."

Ideally, it should be both fixed in libxkbcommon and implemented in compositors as modifiers-only global shortcuts, too (I don't care Xorg much because it's dead technology for me).
libxkbcommon fix would be enough for this particular bug, but implementing in compositors is probably easier to achieve and less error prone.

In KWin we have basic support for modifiers-only shortcuts:
https://blog.martin-graesslin.com/blog/2016/08/modifier-only-shortcuts-available-in-plasma-5-8/
As far I can tell it currently supports one modifier at a time only.
I would appreciate if you could try and confirm it, and then file an separate bug about support of multiple modifiers shortcuts.

Comment 2 Lyubomir 2021-03-31 13:56:57 UTC

Well, i tried adding the following to ~/.config/kwinrc: https://forum.kde.org/viewtopic.php?f=111&t=136932#p366315

Logged out and in again, but the Meta key still shows the Start menu/launcher and doesn't show KRunner. I have no idea if i did it right.

Comment 3 Andrey 2021-03-31 14:52:39 UTC

Thanks for trying.
I've filed related bug 435187, let's track it there.