Bug 466007

Summary:	Blur not applied properly to maximized windows (X11)
Product:	[Plasma] kwin	Reporter:	juuso.maenpaa
Component:	compositing	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	REOPENED ---
Severity:	normal
Priority:	NOR
Version First Reported In:	5.27.0
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed In:	5.27.1
Sentry Crash Report:
Attachments:	As you can see, only a part of the app's window is blurred

Description juuso.maenpaa 2023-02-18 16:24:29 UTC

Created attachment 156442 [details]
As you can see, only a part of the app's window is blurred

SUMMARY
***
I have a semi-transparent theme in the Konsole app and the compositor takes care of the blur effect. However, when I put the app to windowed mode from maximized mode and maximize the app again, the blur only gets applied to a part of the window. This bug doesn't occur on Wayland, where the application window flickers for a moment before the blur gets applied. This bug was fixed in Plasma 5.26.90 IIRC but 5.27.0 re-introduced it.
***


STEPS TO REPRODUCE
1. Make sure you have blur enabled in your desktop effects.
2. Open Konsole and choose a semi-transparent theme.
3. If not maximized, maximize the app.
4. Put the app in windowed mode and maximize it again.
5. The blur isn't applied to the whole application window.

OBSERVED RESULT


EXPECTED RESULT


SOFTWARE/OS VERSIONS
Linux/KDE Plasma: EndeavourOS with the 6.1.12-arch1-1 kernel
KDE Plasma Version: 5.27.0
KDE Frameworks Version: 5.103.0
Qt Version: 5.15.8

ADDITIONAL INFORMATION
https://bugs.kde.org/show_bug.cgi?id=463328
This is the original bug report that got marked as solved, however, the 5.27 re-introduced the bug.

Comment 1 juuso.maenpaa 2023-02-20 08:42:14 UTC

I experimented with the bug a little more and I noticed that whenever I maximized the window, it went to the top left corner, where the blur gets applied and after that it maximized. It seems like the compositor is getting wrong information about the position/size of the window.

Comment 2 Vlad Zahorodnii 2023-02-20 08:48:22 UTC

I can't reproduce it.

Comment 3 juuso.maenpaa 2023-02-20 14:30:06 UTC

(In reply to Vlad Zahorodnii from comment #2)
> I can't reproduce it.

I recorded a video to show it in action:
https://imgur.com/a/x0r1h59

Comment 4 juuso.maenpaa 2023-02-21 21:36:10 UTC

I updated to 5.27.1 and it works now

Comment 5 Vlad Zahorodnii 2023-02-22 08:30:05 UTC

Huh, weird. We made no blur related changes, thanks for the update.

Comment 6 juuso.maenpaa 2023-02-24 14:45:50 UTC

The bug came back in 5.27.1-2 (wasn't there in 5.27.1-1). This is really weird.