Click on the Ubuntu Button (in the top-left corner) and search for CompizConfig Settings Manager and open it.
There scroll down to Desktop section and look for Expo and click it. Click on the Expo key's key-binding and uncheck Enable. That will disable the expo feature. You could also alternatively assign a different key-binding to it.
Install CompizConfig Settings Manager
(CCSM).
Click on the Ubuntu Button (in the top-left corner) and search for CompizConfig Settings Manager and open it.
There scroll down to Desktop section and look for Expo and click it. Click on the Expo key's key-binding and uncheck Enable. That will disable the expo feature. You could also alternatively assign a different key-binding to it.