Actually, it could be the LocalizationDesigner problem that we just recently uncovered. All of the people that created custom controls that inherited our controls would crash VS when they dropped a control on the form. Turned out that it was a problem within the LocalizationDesigner throwing an OutOfMemoryException when it got into an infinite loop of recursive calls.There's a good chance that it might be the same problem.
Here is the link to the newest Extensibility DLL that might resolve the problem. No promises, but, it might work
http://forum.strataframe.net/FindPost9739.aspx