set-resize-corner in canvas<%>

Under Mac OS X, enables or disables space for a resize tab at the canvas's lower-right corner when only one scrollbar is visible. This method has no effect under Windows or X, and it has no effect when both or no scrollbars are visible. The resize corner is disabled by default, but it can be enabled when a canvas is created with the 'resize-corner style.

• (send a-canvas set-resize-corner on?) -> void
     on? : boolean