Q: Switching to another space in mission control

Hi,

Switching to another space on mission control stopped working. Getting myself to mission control is fine, whether by using control + up arrow, or from the trackpad. But once I'm already in mission control, using neither control + left/arrow nor swiping left/arrow works, and it's really frustrating. I checked the system preference and everything is marked, so I don't really get what's wrong.