I was plowing through the 800+ pages of the Windows User Experience Interaction Guidelines (UX-Guide) and found this gem on guide guestions for Group Boxes:
Are all the controls inside the group? If so, indicate the relationship on the larger surface, such as the parent dialog box or page.
Incorrect:
This is the same dialog box that is currently in Vista. It takes guts to bluntly point out ones one mistake (although in this case, since Vista is not a complete re-design, the miss is understandable…almost), so ++ points to Microsoft.
There are tons of other examples using their own existing UI in the UX-Guide.