Switch tabs by mouse wheel in the tab bar ON TABS ONLY

[Admini]

Yes. It's the same in Incognito Mode.

This function is working if the mouse pointer is hovering over the New tab button (the plus sign).
It will still work if I move 50 pixels to the right.
If I go further, the function stops.

I've also tried downgrade to v4.2.10.171, and this function works perfectly as intended.

Safe mode is not Incognito Mode.
You can press Alt+F to show the main menu, and there is a menu command "Restart in safe mode" there.
Click it to enter safe mode.