Error connecting to undo manager of source file "whatever designer"
This error is more than a little irritating, especially considering this is Visual Studio 2005 SP1. I'm getting this, now, for one file, every time I run my application.
The way I "fixed" it was to exclude the file from the Web Application Project, recompile, then re-include, the recompiles.
Seems to me that the error handler that threw this message box should spend more time fixing the problem automatically and less time informing me of a problem I can do little about. Maybe that's just me.