Hmm.. This is curious.
Sometimes I change my display orientation and when I do I expect the mouse / touchpad movement orientation to change as well as well. Well .. it doesn't.
I'll elaborate:
When the display is in landscape mode when I move the mouse forward it moves up on the screen, when I move it backwards it moves down on the screen etc.
When the display is in portrait mode (let's say 90% clockwise) when I move the mouse forward it moves to the right, when I move it backwards it moves to the left etc. I would expect the mouse to keep moving up on the screen when I move it forward and down on the screen when I move it backwards.
This is how things work on Plasma. Do things work the same for everyone? Is there a way to change the mouse / touchpad movement orientation with the display orientation?