I never had this problem before with Tabbed Msn. This is a new pc. When I do Tabbed MSN and have the Tabbed MSNwindows minimalized for awhile, and open it back up, some names of the persons I'm chatting with in the tabs are replaced by a 1. When a person starts chatting with me even though some people are called '1', their name appear normal. Their names will change into '1' later on though. By ESC-ing their windows the problem is solved temporarely.
I suppose it's not a world issue, but it's annoying none the less...
(I hope the screenshot is clear enough.. Imageshack is being a bitch today.. (thanks for hosting anyway ^^))