Can't see Alpha paint on some materials

[SofianeLasri]

Hello, I don't know if this is a bug related to Garry's Mod or Hammer++ (or even if it is related to the materials), but since this problem doesn't occurs on "vanilla" gmod hammer, I think it is Hammer++ related.

Description of the problem

It is not possible to see the paint alpha of some materials on diplacements, not all. The DXT format doesn't seems to be the origin of the problem. In my example I took two DXT 1 vtf7.2 materials.

I am using build 8866.

Screenshots

Hammer++

Vanilla Hammer