Working in Visual Studio 2005 as usual... then all of a sudden... oops, what's this?
The always helpful empty tab with No Icon. 
* Edit 1/19/2006, 2:33 pm *
I believe this is a bug in the TFS Beta 3 Refresh client. I now get an error about a source control plugin not being installed properly error message. I've never seen this problem before until installing the client recently.
And also, to get rid of the empty tab: expand the tab, right click the header, and select hide.