-through \fBmenu_driver\fR. This routine has three major input cases; either
-the input is a menu navigation request, it is a printable ASCII character or it
-is the KEY_MOUSE special key associated with an mouse event.
+through \fBmenu_driver\fR. This routine has three major input cases:
+.TP 3
+-
+The input is a form navigation request.
+Navigation request codes are constants defined in \fB<form.h>\fP,
+which are distinct from the key- and character codes returned by \fBwgetch\fP.
+.TP 3
+-
+The input is a printable character.
+Printable characters (which must be positive, less than 256) are
+checked according to the program's locale settings.
+.TP 3
+-
+The input is the KEY_MOUSE special key associated with an mouse event.
+.PP