Hi Casiopea -
To answer your question, I'm not sure I've ever actually seen a ring, enum, or radio button control exhibit the "CTRL+click" behavior you're describing. (In fact, I think all of those user interface elements are designed specifically so that only one value can be selected at any one time.)
However, I have seen plenty of list boxes allow multiple selection, and LabVIEW's list boxes can do the same. A group of checkboxes can also end up looking like radio buttons if you group them with some "decoration" and would allow you to select multiple options (because you can check/uncheck each box independently).
I'm not quite sure, though, how your question relates to LEGO specifically. Did you accidentally post this question to the wrong discussion forum?
To address Eagles Coach's statements, the official Move block uses checkboxes in the "Port" section of the configuration pane in the MINDSTORMS software, not radio buttons. The Motor block uses mostly radio buttons, and I didn't see any sections that allow multiple selections.
------
James Blair
NI R&D