Since a week or so I seem to have sort of the same problem with pidgin (2.5.2).
I used it for various accounts but as soon I log in with just one account and type
a message the pidgin window turns gray and stays that way. I've tried to remove it
completely to install it again afterwards but no luck. I'm not sure if it's related to mint 6
on my computer though because I used mint 6 in combination with pidgin for a couple of
weeks without any problems.
I really hope that there's some kind of solution for this because for some accounts i can
only use pidgin
Greetz & take care