Created attachment 170630 [details]
Video showcasing the snapping issues described

SUMMARY

Firefox with title bar disabled (using csd) and some other applications that provide a csd will unsnap if the top of the screen in the snapping region is clicked. This becomes an issue with tab reliant applications as often you will be clicking towards the top of the screen. I have attached a video that showcases the bug, note that when the window is snapped to the bottom this issue does not happen.

This is an issue specific to Plasma and is not specific to plasma 6 I have been able to replicate this on much older versions of plasma 5. Other desktop environments/wm's such as Gnome, xfce, cinnamon, sway don't seem to exhibit this issue and I don't believe it to be wayland or x11 specific.

Custom tiling is also affected by this but again only when the window is adjacent to the top of the screen. Surprisingly it also does not matter the amount of padding added by the custom tile.


STEPS TO REPRODUCE

Quick Tiling
1. Open firefox
2. Snap to either half of the screen or a quartile at the top of the screen
    (alternative. use custom tiling and drag window on to a tiling region adjacent to the top of the screen)
3. move cursor to top of the screen till cursor changes to the resize cursor.
4. Click once and the window will remove its snapping as if the window was dragged.

OBSERVED RESULT
the window will remove its snapping as if the window was dragged.

EXPECTED RESULT
The window will not un-tile and will only change size if dragged, same as other applications

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Fedora Rawhide / Fedora 32 / Fedora 40 - KDE Spin
(available in About System)
KDE Plasma Version: 5.20...6.1

Video Attached with bug below.

ADDITIONAL INFORMATION