Been using Thunderbird for ages. This problem has been occurring for a good chunk of that time. Every so often, as I'm reading through my email, Thunderbird will freeze/stop responding. Clicking on the window while it's in this state will cause it to fade gray (the typical thing Windows does with programs that aren't responding). I can still switch to other programs, which work fine. After a few minutes, Thunderbird will start working again, but it's only a matter of time until it freezes again. Almost guaranteed to happen within 5-10 minutes of opening Thunderbird, syncing mail, and starting to read. Highly annoying. Any ideas?