def rgbmap_cb(self, rgbmap, channel):
        """
        This method is called when the RGBMap is changed.  We update
        the ColorBar to match.
        """
        if not self.gui_up:
            return
        fitsimage = channel.fitsimage
        if fitsimage != self.fv.getfocus_fitsimage():
            return False
        self.change_cbar(self.fv, channel)