Every once in a while I see the workspace switcher popup jump to the left/right. It seems to me like its x (and y?) position is not correctly updated when it is resized because workspaces are added and removed.

I can easily reproduce it here when I have five workspace open at a time. I do the following only using keyboard shortcuts:
 1. Place two windows on the last workspace
 2. Switch workspaces a couple of times (just to make sure the placement is correct)
 3. move one of the windows down to create a new workspace.
 4. go two workspaces up
 5. watch closely, at the second press the switcher popup is centered again and jumps to the right.