From one week ago, I am experiencing this issue with a USB mouse on Kubuntu 12.04: the mouse pointer doesn't move unless I hit a click on the left button. After the click, it moves regularly, but as soon as I stop it, it needs another click to reactivate. The weird thing is that the same mouse behaves normally on my desktop computer, which has the same linux distribution with the same updates.

Update: I realized that on my laptop this happens only when the machine runs on battery.