caption                                       (Assignable)

        Contains a character string that concisely describes the radio group
        on the screen.

        When present, the & character specifies that the character
        immediately following it in the caption is the radio group's
        accelerator key. The accelerator key provides a quick and convenient
        mechanism for the user to move input focus from one data input
        control to a radio group.  The user performs the selection by
        pressing the Alt key in combination with an accelerator key.  The
        case of an accelerator key is ignored.