* - Before we perform a hit test within a layer, we check if all the layer's parents are visible
* and sensitive.
* - If they are not, we skip hit testing the actors in that layer altogether.
+ * - If a layer is set to consume all touch, then we do not check any layers behind this layer.
*
* - Actors
* - The final part of hit testing is performed by walking through the actor tree within a layer.