SUMMARY
The mouse button references under Window Management>Window Actions do not properly account for the Left Handed setting under Input Devices>Mouse.

STEPS TO REPRODUCE
1. Under Input Devices>Mouse, set mouse to left handed 
2. Go to Window Management>Window Actions>Inactive Inner Window
3. Set Right button to Activate, Raise & Pass Click
4. Set Left button to Activate & Raise

OBSERVED RESULT
Left mouse button performs Activate, Raise & Pass Click
Right mouse button performs Activate & Raise 


EXPECTED RESULT
Left mouse button performs Activate & Raise
Right mouse button performs Activate, Raise & Pass Click


SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: Mageia 7
(available in About System)
KDE Plasma Version: 5.15.4
KDE Frameworks Version: 5.57.0
Qt Version: 5.12.6

ADDITIONAL INFORMATION
It appears that on the Window Actions page  "Left button" actually means "button 1" and "Right button" means "button 2," and they are not actually mapping to the physical mouse buttons as set by the Left Handed option.