I have this issue where the entire text in text boxes is selected whilst I'm typing in it. For example, in FireFox search box I'd try to type "foo" but end up with "o" because I managed to type "fo" before everything was selected, and then typed "o" which replaced the "fo".

When it happens, it is incessant - not just a one-off. But it doesn't happen all the time, and I haven't managed to figure out what causes it to start and stop.

Is this a known problem with an easy solution?

EDIT: this has nothing to do with touchpad. I get this occasionally even on a machine without one. I can usually rectify the issue just be alt-tabbing about a few times.