I lost a few before that just became blank, but now they are all gone. Some come back when opening the page again, but not all. (see screenshot below)

What causes this and is there an easy way to solve this ?

Thanks !

Additional info: I run several cleaning programs every day, nothing new.

ps, the message editing function of ThaiVisa is corrupted, can this be a Firefox 4 error ?

FF4 is beta 'nuff said.