Judging from your screenie, I would say you have your own class sysdiagram in the VS2010WinTest namespace. So when you rename that class, you are in the clear again. You would have the same issue in VS2008, by the way, if you were to use the same code there
as well. but with a namespace that includes VS2010 in the name, I would think you have yourself a VS2010 project.
But to see where the class is located, just create a new reference to the class like so:
And then put the cursor on the word sysdiagram, hit F12 and you will jump to the code that declarese the sysdiagram class. If it is not in your source code, it will create a source file from MetaData, with all methods and property signatures.
Hope this helps