I can't rearrange full screen spaces in mission control. When I drag one to move it, it never seems to stick back onto the mission control bar. If I drop the space on the bar the animation shows it going back to the dock and it disappears from the mission control bar. I can drag the space from the bar to the desktop.
It tends to leave behind a semi transparent image of the full screen view (similar to the one that can be dragged around in mission control) and this persists even after mission control is closed. The only way to get rid of it is to restart my machine.
What's going on and how can I fix it?