Adds this control to the specified map x, removes this control from its current map, or returns the current map. This method is typically not called directly, but is needed to support the map’s add and remove methods.
If the argument x is specified, this method returns this. If x is null, this control is removed from its current map; otherwise, this control is added to the specified map. If no arguments are specified, this method returns the current map, which may be null. Whew!