I think that I may have found a bug in CEGUI. I'm using v0.6.1. I have searched the forum and I couldn't find any similar bug report.
It's about the alpha value for windows. The value seems to be circular. i.e. when the alpha is 0.5 and I add 0.9 to the alpha value, it doesn't correct the value to 1.0, but it rather sets it to 0.4 (as if it was "(0.5 + 0.9) % 1.0"). The same happens with decreasing values (0.6 - 0.9 becomes 0.5).
I hope that it gets fixed soon, it's kind of annoying.
