Joep,I think that the enum window actually went away (due to an error of some kind). When this happens, the wait window generally sticks around until you get out of Visual Studio and come back in.
So in regards to your problem, let's try something and see if it works. When the builder appears do the following:
1. Type in: SqlDbType
2. Press Enter to execute the search
3. It should appear in the list
If not let me know and we can dig a little deeper.