[vtkusers] BUG : vtkLookupTable Transpacency == background color?

[John Biddiscombe]

> Unfortunately removing this call did not fix my problem
> -- the areas that are supposed to be transparent are
> still colored with the renderer's background color.

Hmmm. I just tried it and got the same results. Transparent region actually
looks like the background - and not transparent. I put some other objects
behind to make sure, but they were obscured. I smell trouble....

I've inserted BUG in the title and maybe someone else will have a look (I
can't right now....)

JB