Problems with lighting in 2.0

[david]

As a follow up, I have lighting pbs when I switch textures on an object. Basically, when I switch textures on a self-illuminated object, the object stays as bright as originally, as long as all the textures are non-transparent.
However if I use a transparent texture it seems to mess up the flag for .appearance. As a result if I go back to a non-transparent texture, and if the object is on the side (not in the head light range), it appears darker than originally. So I need to set the flag for .appearance to viz.DECAL. And then if I try to reapply a transparent texture, the transparency is not rendered anymore so I need to set the flag to viz.MODULATE to get the transparency back. It is a little bit of a hassle, but in my case I could track easily the transparency of the texture.