I think this is something that has to be looked at. If you happen to use AcceptButton, CancelButton, StartPosition and such, you will get a compilation error. AcceptButton is a member of System.Windows.Forms.
Prefixing those widget name might solve the problem, but I believe there is a deeper problem here with regards to name usage determination by the compiler, widget name and property name collision, and ambiguity decision. There are thousands of objects in .NET, this could invalidate a lot of words depending on the how the USING is scoped.
Did you report that issue to tech support? I have a similar issue logged (when enums compete with database field names).
Reporting it to tech support is the way to get it fixed.
Reporting it to tech support is the way to get it fixed.
Using some version of Hungarian notation is a good way not to have the problem ...