I recently reinstalled my opensuse to fix a nvidia driver mess. Now when I move my mouse to the bottom of the screen it scrolls the screen with around one inch of blackness at the bottom of the desktop. I can scroll it back up and than my desktop fits the screen. Well hopefully someone can understand what I am saying.
Not so sure about the issue for bottom… but you can give this a try:
Desktop settings → Desktop → Screen Edges. Change the edges according to your need.
Hope, this is what you are looking for.
That did not resolve the issue. When I slide my mouse to the bottem of the screen it pushes my desktop up (cutting off the top of my desktop) creating a black space at the bottem of the screen. I can fox this by sliding my mouse to the top of the screen and sliding further than the monitor.