ArcWeb Explorer JavaScript API automatically assigns depths to the various layers added to your map. It also allows you to set the depth for your layer.
When layer depths are set automatically, the layer capturing mouse clicks is automatically positioned on top of all the other layers so it is possible to interact with the map. You don't have to worry about setting depths for any layers or the click layer.
If a layer is removed, the layer order automatically reshuffles to fill the gap.
When manually setting layer depths using the "depth" argument of the AWMap addGroupLayer method, the following should be kept in mind:
If these conditions are not met, the map may not behave as expected, in terms of capturing clicks.