Visual Studio: File type xxx conflicts with imported type: xxx

I like to use my own User Controls and Web Controls in my web projects, and when I was building the current one on a lovely morning at 4am, Visual Studio 2005 bombed me with 365 warnings (one for each day of the year:))  stating there's a type conflict in my project. What the hell?:) I really hate errors and warning messages, so I checked what happened:  when i created a web control in my project, and dropped the control to a webpage in design view, visual studio 2005 added the /bin/projectname.dll as a reference to the project itself - and when i was building, the two dlls (the old and the new) had the same types. the solution was to remove the self-reference... update: i found the same error reported on Microsoft Connect.