Enables or disables a window so that input events are ignored. (Input events include mouse events, keyboard events, and close-box clicks, but not focus or update events.) When a window is disabled, input events to its children are also ignored.
The enable state of a window can be changed by enabling a parent window, and such changes do not go through this method; use on-superwindow-enable to monitor enable state changes.
If enable? is #f, the entire radio box is disabled, otherwise it is enabled.
If enable? is #f, the nth radio button is disabled, otherwise it is enabled (assuming the entire radio box is enabled). Radio buttons are numbered from 0. If n is equal to or larger than the number of radio buttons in the radio box, an exn:application:mismatch exception is raised.