SUMMARY It start happening after recent update. STEPS TO REPRODUCE 1. Alt + Tab 2. Square appears 3. Hold Alt 4. Arrow 5. Square disappears 6. Arrow 7. Square appears OBSERVED RESULT When changing windows with arrows yellow square appears every second Arrow key or Alt + Tab press EXPECTED RESULT No unidentified squares above the clock SOFTWARE/OS VERSIONS Operating System: Kubuntu 22.10 KDE Plasma Version: 5.25.4 KDE Frameworks Version: 5.97.0 Qt Version: 5.15.4 Kernel Version: 5.15.0-46-generic (64-bit) Graphics Platform: X11
Seems like graphical corruption. Is the square at all interactive? What graphics hardware are you using?
Created attachment 151757 [details] yellow square with text
GPU 0: NVIDIA GeForce GTX 1660. It's not graphical corruption. I can type in this square. Now this square is "always on" on desktop, as on screenshot.
Looks like that's a Notes widget that lives on your desktop. You can move it by clicking-and-holding and then dragging it elsewhere. The fact that it appears while you alt-tab is probably because of the default setting to hide other windows, so parts of the desktop appear. Evidently the part of the desktop that shows this widget is being shown.
I can't move it. I removed it in edit mode. I do not use notes, sticky notes, whatever... I didn't add any widgets. This thing appeared after upgrade. That's strange.