This is one of various DE issues I am struggling with since I upgraded to Ubuntu 18.04. After a couple of days I started feeling some pain in my right wrist. I now realise the mouse speed was reduced in the upgrade and thus I am no longer able to move the pointer from one edge of the screen to another in a single movement. I have tried to tweak mouse speed in the Settings > Mouse & Touchpad dialogue, like I used to do in previous Ubuntu releases:
This however, has no effect. The pointer speed seems to be stuck at the middle, ignoring whatever is displayed in the dialogue.
Is there any other way of changing mouse speed on Ubuntu 18.04?