SUMMARY


STEPS TO REPRODUCE
1. Edit a file in Kate, use mouse wheel for vertical  scrolling.
2. 
3. 

OBSERVED RESULT
Vertical scrolling with mouse wheel suddenly stops working.

An existing Dolphin window also has wheel scrolling broken.

If I create a new Kate window (File -> New Window), wheel scrolling still doesn't work in the new window.

If I create a new Kate window by running "kate" in shell, scrolling works.

If I create a new Dolphin window (File -> New Window), scrolling works.

If I enable "Press MMB and move mouse for scrolling" in SystemSettings->Mouse, the mouse pointer stays still when attempting to scroll (as expected), however the file in Kate doesn't scroll.

Scrolling keeps working in Chrome.

Scrolling keeps working in Libreoffice Calc.

Scrolling stopped working in Anki (Qt6/PyQt-based).

Scrolling stopped working in Telegram (Qt6-based).

EXPECTED RESULT
Scrolling should keep working.

SOFTWARE/OS VERSIONS
Operating System: Fedora Linux 41
KDE Plasma Version: 6.3.4
KDE Frameworks Version: 6.14.0
Qt Version: 6.8.2
Kernel Version: 6.13.11-200.fc41.x86_64 (64-bit)
Graphics Platform: X11
Processors: 8 × Intel® Core™ i7-6700HQ CPU @ 2.60GHz
Memory: 15.4 ГиБ of RAM
Graphics Processor 1: Intel® HD Graphics 530
Graphics Processor 2: NVIDIA GeForce GTX 960M

ADDITIONAL INFORMATION