I have found that making a few phone calls with quick succession causes this to happen. Doesn't matter whether you make or receive the calls, but 2 or 3 calls quickly after one another is enough to make this phone poo itself and all my widgets are gone.

Oh and putting a call on hold whilst answering a call coming through on call waiting is sure to make my widgets go down faster than a Taiwanese hooker.

I've got Desktop activity manager running which helps me restore all my widgets quickly, but I found myself making and taking quite a few phone calls this arvo which wasn't much fun