I am really new to lxde. This last weekend I download the sources (lxde stuff and dependencies), compiled, packaged and installed on my Slackware box. LXDE runs nicely and fast (but that's no news for you right

But then when I try to change the theme, using lxappearance, nothing happens. There are lots of themes to be chosen, none seem to work. I tried to change the icons, same result.
Any hints?
Specs (need more info?):
Slackware64-current (on my desktop) and Slackware-current (on my netbook)
gcc-4.5.1