How do you control Z-order of entities in Seesaw(clojure)?

Question

I have a window with an xyz-panel that holds a bunch of labels. Now some of them have to overlap and I can't figure out how to set the Z-order.

(defn- mk-smhi-frame
    "create the frame"
    []
    (sc/window
        :width 1920
        :height 1080
        :content
        (sc/xyz-panel :items [
            ; begin snip
            (sc/label :id         :clock
                      :bounds     [1000 0 920 500]
                      :paint      draw-clock)
            ;----------------------------------------------
            ; how do make :radar be on top of :clock?
            ;----------------------------------------------
            (sc/label :id         :radar
                      :bounds     [1200 100 500 300]
                      :paint      draw-radar)
            ; end snip
            ])))