Comment 5 for bug 850093

I have the same issue, that Pidgin does not schow his window.
The Pigin icon in the left panel does not work and the message menu, also. I have to close pidgin first and start it manually, after this the buddy-windows shows up. After minimizing it it is gone...

 I think it is Unity or Compiz related and i think the window is there on the desktop but it is invisible (I could not click at other applikations like firefox, close or move does not work, seems to be hidden from something - perhaps related to the invisible windows bug which was reported from sam splillaz sometime before on his blog)
Ḿaybe my report is helpful for you.