# File vtk/gtk/GtkVTKRenderWindowInteractor.rb, line 127
    def OnRealize(self, *args)
        if self.__Created == 0
            # you can't get the xid without the window being realized.
            self.realize
            win_id = str(self.get_window.xid)
            self._RenderWindow.SetWindowInfo(win_id)
        end
    end