Visual Studio 2010 - XAML Editor Extraordinarily Slow

Has anyone else experience incredibly slow performance in the XAML editor in VS 2010? If I have a new project with a limited number of files, the performance is fine. However, if I have a project with a larger number of XAML files, the XAML editor hangs intermittently every few seconds, making it almost impossible to use.

I should also note that the performance is only slow in one particular project where I am referencing DevExpress 2010. I am not certain if this is related.

Any suggestions on solutions to this problem would be greatly appreciated.

Chris