# File vtk/gtk/GtkVTKRenderWindowInteractor.rb, line 226
    def OnEnter(self, wid, event)
        """Entering the vtkRenderWindow."""
        self.grab_focus
        m = self.get_pointer
        ctrl, shift = self._GetCtrlShift(event)
        self._Iren.SetEventInformationFlipY(m[0], m[1], ctrl, shift,
                                            chr(0), 0, nil)
        self._Iren.EnterEvent
        return gtk.TRUE
    end