I've just tried it with newest version of RichFaces and it works fine for me. What browser are you using? Please make sure that you set shadowOpacity with a number between 0 and 1.
i'm using ie 8 and firefox.
i dont understand why works fine in your browser because i only write this:
This is my popup
When i open the popup the background by default is gray without opacity.
If i try put the property shadowOpacity it's the same
I dont understand why do it....with rich faces 4.0 final works fine! but with 4.1dont works fine!