It has become a common practice for software developers to use more than one display and unfortunately the code and diagram Windows within Visual Studio 2008 SP1 are locked within the Visual Studio frame.

According to blog posts by Chris Bowen and Noah Coad this has been a request the team has been hearing a lot and the good news is that Visual Studio "10" provides support for multiple displays and according to the
feedback item on Connect this has now been closed as fixed.

[via IntelSoftwareBlogs]