         if not l.added
             l.addTo map
             l.added = true
+
+    if year_changed
+        redraw_buildings()
+
 
 # When the map starts moving, remove all non-visible layers
 # to save on bandwidth cost.

    $("#year_b").html orto_years[state.layer_a_idx + 1]
    $("#year_a").css {opacity: 1 - state.layer_b_opacity}
    $("#year_b").css {opacity: state.layer_b_opacity}

    # Set visibility flags on all layers and hide the non-visible layers.
    for al in orto_layers

update_years = (state) ->
    year_a_idx = state.layer_a_idx
    opacity = 1 - state.layer_b_opacity
    for year_el, idx in $("#year_list div")
        if idx == year_a_idx
            opa = opacity * (1 - MIN_OPACITY)
