Newish to Linux, and have been testing out CachyOS (Arch) and Nobara (Fedora) using KDE Wayland, as Windows 10 dies a slow death. I’m having a couple issues in KDE. One of them is a graphical issue when sliding windows across the desktop. The edge of the window is leaving lines across the desktop. And they sit there and flicker until I do something to make them go away. Which is basically holding down left button on the mouse and dragging that like you’re selecting items. That clears out the lines.
The KDE bug site says to post in the forum first before reporting a bug. I did a couple searches with the current reported bugs, and didn’t see this particular bug, but there are a lot of bugs, so it would be easy to miss. I will put this in two sections. Where it does happen and where it doesn’t happen:
Happens in both KDE Plasma desktop on CachyOS (Arch) and Nobara (Fedora). It happens when sliding windows like Konsole or Dolphin across the desktop. It does not happen when I slide the browser window, for some reason.
What I’ve tried to fix the issue, per suggestions from others. Tried open source drivers, proprietary drivers, disabled GSP firmware. Turned off all animations. Variable refresh on and off (on causes more issues). Task bar (panel) from floating to fixed and also set to hidden and not hidden.
- ** Where it does not happen**
This does not happen when I switch to X11. Surprisingly, this also does not happen using Gnome DE in Wayland. So, no X11 and no Gnome Wayland tells me it is likely a KDE/Wayland issue.
If you are going to suggest anything else to troubleshoot, it has to be simple for the stupids who aren’t very experienced in Linux yet. And also whether this needs a bug created or not. Or wait for a future updated. Image below on the issue:
https://imgur.com/a/kk6rjW3
Hi! The fact that it’s occurring for KDE applications, but not your browser window, makes me wonder if it has something to do with the native window decorations (titlebars and borders).
Does this issue occur if you use the default Breeze settings in System Settings > Colors & Themes > Window Decorations?
If it still does, can you double-check clicking the Edit button on the Breeze decorations:
And try setting the defaults for the Shadows and Outline tab:
This sounds like a possible re-occurrence of an issue that had been thought to be solved: 500185 – Moving windows with no shadows/wobbly windows effect leaves artifacts behind - checking the configuration changes above might help narrow that down 
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Well hot damn. That was exactly it. Changing the window decoration to the “Plastik” one was it. And that also was the source of my other issue(s) as well. Changing back to default “Breeze” fixed those issues. Everything seems fast and smooth. Guess I can’t use Window decorations at the moment. At least not the Plastik one.
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Well, I’m glad we’re at least closer! Now one other question to figure out where this should go within the KDE Bugtracking System - if you set the shadows for the Breeze Window Decorations to “None”, does the issue come back?
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Hi, John. Yes, the issue definitely comes back when disabling shadows. Turning shadows back on resolves the issue.
Aha! One last thing to ask then - on that bug report I linked above, could you please leave a comment with your system information from the Info Center application (like the format below), confirming that the issue is still occurring on your device? That way, developers can know that the issue isn’t totally squashed, and can still be reproduced
Thanks!
Operating System:
KDE Plasma Version:
KDE Frameworks Version:
Qt Version:
Kernel Version:
Graphics Platform: Wayland
Processors:
Memory:
Graphics Processor 1:
Graphics Processor 2:
Manufacturer:
Product Name:
System Version:
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Will do. Thanks for the help!
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