edit: I found the solution
The culprit was onboard, which allows you to activate this - but it persists even after onboard is closed
See https://discourse.nixos.org/t/how-to-turn-off-gnome-hover-click-on-kde-plasma-and-why-did-it-get-activated-in-the-first-place/36643 for details
orginal post
Since yesterday my laptop/tablet (a shiftbook/shift13mi) with nixos and kde plasma shows hover click behavior (i.e., whenever I hover my cursor over something clickable like a button or a link a timer is going down and then it clicks the thing). I did not consciously activate it and it is VERY annoying. After a reboot it was still there but I saw the following window attached to this post.
Searching for it so far has only brought me the insight that KDE Plasma should not even have hover click, only gnome has that. Any idea what is going on and how to fix it?
About my system:
Operating System: NixOS 23.11
KDE Plasma Version: 5.27.9
KDE Frameworks Version: 5.112.0
Qt Version: 5.15.11
Kernel Version: 6.1.64 (64-bit)
Graphics Platform: X11
Processors: 8 × 11th Gen Intel® Core™ i5-1135G7 @ 2.40GHz
Memory: 31,1 GiB of RAM
Graphics Processor: Mesa Intel® Xe Graphics
While I did not figure out a solution yet, but I found out some additional information and came to the conclusion that nixos must have built something weirdly. Thus I posted on the nixos forum and will likely only update there: https://discourse.nixos.org/t/how-to-turn-off-gnome-hover-click-on-kde-plasma-and-why-did-it-get-activated-in-the-first-place/36643
