Bug 470175

Summary: Without focus, XWayland apps cannot get Clipboard/Selection change events from Wayland apps.
Product: [Plasma] kwin Reporter: shenlebantongying <shenlebantongying>
Component: wayland-genericAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED INTENTIONAL    
Severity: normal CC: kde, nate, niuchangcun, rosswzyang, xaver.hugl
Priority: NOR    
Version First Reported In: 5.27.5   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description shenlebantongying 2023-05-23 17:46:30 UTC 
SUMMARY
Since KDE5.27, if an XWayland app doesn't have focus, then the QClipboard::Changed won't happen if a user copy text from Wayland apps.

Minimum code sample: https://github.com/SourceReviver/wayland_clipboard_xwayland_bug

STEPS TO REPRODUCE

1. Run the mini code sample above
2. Select or copy text from somewhere else

OBSERVED RESULT

The label from the sample code won't change unless the window got focused again.

EXPECTED RESULT

The label should change despite having no focus.

ADDITIONAL INFORMATION

* This only happens when copying text from Wayland to the XWayland apps.
* On KDE 5.26, the sample code can detect clipboard changes without focus 
* The sample code works OK on GNOME Wayland but not OK on Sway, and I don't know if this is intended. 
      * However, I don't find anywhere in the standards about this detail.


SOFTWARE/OS VERSIONS

ArchLinux
Comment 1 shenlebantongying 2023-05-23 18:08:54 UTC 
The sample should be run with
```
QT_QPA_PLATFORMTHEME=xcb ./wayland_clipboard_bug
```
Comment 2 Nate Graham 2023-05-24 18:56:20 UTC 
Also not sure if it's intentional.
Comment 3 rosswzyang 2023-05-25 13:47:53 UTC 
(In reply to Nate Graham from comment #2)
> Also not sure if it's intentional.

related app bug
https://github.com/xiaoyifang/goldendict-ng/issues/741
Comment 4 David Edmundson 2023-06-11 21:49:29 UTC 
>Also not sure if it's intentional.

It's definitely intentional. 

>Meanwhile, it works OK on GNOME Wayland.

That's the more surprising twist.
Comment 5 Vlad Zahorodnii 2023-06-12 07:45:03 UTC 
> That's the more surprising twist.

mutter doesn't check whether the client is focused unlike kwin or sway.
Comment 6 rosswzyang 2024-01-24 14:56:25 UTC 
(In reply to Vlad Zahorodnii from comment #5)
> > That's the more surprising twist.
> 
> mutter doesn't check whether the client is focused unlike kwin or sway.

this issue is still existed on plasma 6 / kwin 6
Comment 7 Zamundaaa 2024-01-24 15:51:16 UTC 
It still exists because it's intentional
Comment 8 rosswzyang 2024-01-25 14:16:34 UTC 
(In reply to Zamundaaa from comment #7)
> It still exists because it's intentional

while, some x11 apps like goldendict is useless on plasme, maybe we should add some switchs in "legacy x11 app support"