Weird simple texturing behaviour


I’m exploring Panda3D through a running project and I’ve stumbled upon some strange behaviour. I’m slowly trying to develop a system that allows for Vagrant Story style text bubbles and, when I apply a test texture with some transparency to a text node that is fully opaque, I see the text node’s card showing through the texture. I guess that’s fair enough, but if I set the text node’s card’s opacity to 99%, I don’t see the background colour anymore. And if I set the card’s opacity to 0%, I can’t see the texture. So is there some kind of logic behind this? And is there a cleaner solution than setting opacity to 99% when I really mean 100%?

If you’d care to look at the code and a few screenshots of this effect, please check out the link in my signature.