def METHOD_NAME(self, ctx: cairo.Context):
    if self._selected is None:
        return
    if self._selected.level_id != self.level_id:
        return
    x, y = self._get_marker_xy(self._selected)
    x, y, w, h = (x - RAD * 2, y - RAD * 2,
                  RAD * 4, RAD * 4)
    ctx.set_source_rgba(0, 0, 1, 0.6)
    ctx.rectangle(x, y, w, h)
    ctx.fill()