HighlightLayer problems

I found two issues regarding the HightlightLayer:

1: The implementation of the HightlightLayer is using Mesh.id to manage the meshes internally. This is a problem because the id may not be unique (as default its the same as Mesh.name). In my projects i usally don't care about the id or the name and that makes it difficult for me to use the HightlightLayer.
Here is a Playground to show the problem: http://www.babylonjs-playground.com/#2IIVG2#0
Box2 should not be red but it is because both boxes have the same name. Maybe the implementation should be changed to use Mesh.uniqueId instead of Mesh.id.

2: The HightlightLayer can't be used in combination with renderingGroups.
Here a playground: http://www.babylonjs-playground.com/#2IIVG2#1
The highlight of box1 is not rendered correctly because box2 uses renderingGroupId 1 (line 15).