What OS/browser are you using? I have no idea what you are talking about. The only time I have ever seen anything like what you are describing is when maybe something is messed up with flash or an external pdf viewer. But even that doesn't freeze up the mouse.
Also I am a pretty heavy browser user, I have 20+ tabs open on average and a bunch of plugins.
Usually use Chrome on a Win7. I've seen this happen about once a day or every other day. Comment got upvotes so I guess I'm not alone in this experience?
Also I am a pretty heavy browser user, I have 20+ tabs open on average and a bunch of plugins.