I recently moved to a machine with 64-bit Windows. When I try to debug a winforms user control with the test container that's included in Visual Studio Team System 2008, I just get an empty test container and the user control does not load. Nothing even shows up in the list of controls that can be loaded. I hope that there is something obvious that I'm missing.
Also, if I click load and try to load the usercontrol dll, I get an error that says that "Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information."
EDIT: I tried creating a simple user control in a new project with only a text box on it. I was able to get it to load in the user control test container as long as I compiled AnyCPU. If I compiled as x86, it wouldn't load.
I tried compiling one of our exisiting user controls in AnyCPU and running it, but still got an empty test container. I suspect that it might be because all of our user controls have references to assemblies compiled in x86. Incidently, I can drop the user control in a test winforms app and debug it that way. So, I have a work around. It's just not as efficient as being able to fire up the user control test container at will.