I'm not sure if there ever were such feature as auto-hide/show when mouseover, like there were in WindowManager, i just cant find it anyway.
Just like Firehalk says theres seems to be quite a problem because almost every combination of options i've tried results in a frame around the contactlist which disappears and reappers every third second or so. Even tried to reinstall WLM and plus and removing all scripts and stuff. though nothing works