I was running Ubuntu 13.10 with no issues and decided to upgrade to Ubuntu 14.04 recently. Since I've upgraded I've noticed that my mouse starts to lag after I play a movie via xbmc or a video on Youtube in full screen mode.
It usually happens after playing a fullscreen video for around an hour. My mouse works perfectly on startup.
I have just tried a fresh install of 14.04 and I've got the same problem.
When I say the mouse lags, I mean that after I move the mouse it takes 1-2 seconds to respond and is continuously lagging ie. once it starts lagging it's constant and I have to reboot to fix the problem. I've tried restarting x but that doesn't fix it.
I am using a Logitech K400 mouse/keyboard combo with a logitech unified receiver.