I am trying to find how to turn this off and can’t find it.
What I tried to describe in the title was what happens when, by accident, I move the cursor to the extreme top left corner of the screen.
At that time, every window I have working will be displayed. It looks like it was meant to be an easy way to be able to switch between running apps.
I just want it turned off.
That’s the “present windows” effect, that’s triggered by default when you move the mouse to the upper-left corner.
You can configure the “Screen Edge Actions” in “Configure Desktop”->“Workspace Behavior”->“Screen Edges”->
Click on the square in the upper-left corner of the symbolic screen there and choose “No action” (or whatever you like) from the menu.
Another option would be to disable the “Present Windows” effect completely in “Configure Desktop”->“Desktop Effects”->“All Effects”.