A replacement for synaptiks is being worked on for 14.04 which (if I recall correctly) has a tray icon which provides this ability. Unfortunately this won't be fixed for synaptiks (i.e. any release before 14.04).
A replacement for synaptiks is being worked on for 14.04 which (if I recall correctly) has a tray icon which provides this ability. Unfortunately this won't be fixed for synaptiks (i.e. any release before 14.04).