STEPS TO REPRODUCE 1. Enter edit mode for panel 2. Click 'More Options' 3. Enable 'Windows Can Cover' 4. Exit Edit mode 5. Make sure 'Screen Edges' is enabled in Desktop Effects. 5. Move mouse cursor to bottom of screen slowly. OBSERVED RESULT The Screen edge blue glow appears above the panel. This covers the icons slightly and has led to me and a friend concluding that it was a graphical bug. It's even worse if you've done what I did and reduced the size of the panel. EXPECTED RESULT There shouldn't be an unexplained blue glow appearing over user interface elements by default. SOFTWARE/OS VERSIONS Operating System: Manjaro Linux KDE Plasma Version: 5.23.4 KDE Frameworks Version: 5.89.0 Qt Version: 5.15.2 Kernel Version: 5.15.12-1-MANJARO (64-bit) Graphics Platform: X11 Processors: 8 × Intel® Core™ i7-4820K CPU @ 3.70GHz Memory: 15.6 GiB of RAM Graphics Processor: NVIDIA GeForce GTX 1070/PCIe/SSE2 ADDITIONAL INFORMATION Because the screen edge highlight only seems to show up when you move the mouse slowly to the edge of the screen, it feels like an intermittent problem to a new user. Most new users will return to the Edit mode for the panel to see if there's an option to stop the blue glow, but there isn't. Instead, this option is hidden in a list of desktop effects in system settings. I'm using the Breath Dark theme, not sure if that helps too.
Can reproduce.
I'm afraid the "Windows Can Cover" Panel visibility mode has been removed for Plasma 6 and we aren't planning to bring it back. In its place, we plan to implement an "intelligent auto-hide" or "dodge windows" mode, per Bug 349785. This should hopefully be much better than "Windows Can Cover" ever was, and offer support for its use cases. Thanks for your understanding!