class interface MOUSE_HANDLER creation make (win: like parent) -- Create the mouse handler for one button. ensure down: not is_down and not dragging; keep_reference: win = parent feature(s) from MOUSE_HANDLER -- Parent window parent: WINDOW -- Associated window. feature(s) from MOUSE_HANDLER -- Mouse button status is_down: BOOLEAN -- Is the button down? point: POINT -- Current position of the mouse pointer. invariant valid_point: point /= Void; end of MOUSE_HANDLER