FF4.0的自动隐藏侧边栏CSS失效了？能修正吗？

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");

#sidebar-box {min-width:0;  max-width:1px!important;  overflow-x: hidden !important;}

#sidebar,#sidebar-title,#sidebar-box .tabs-closebutton {visibility:hidden;}

#sidebar-box:hover {max-width:none!important;}

#sidebar-box:hover #sidebar,#sidebar-title,#sidebar-box .tabs-closebutton {visibility:visible;}

#sidebar-splitter {border-width: 0px!important; min-width: 0!important; max-width: 0!important;}

#sidebar-box:hover + #sidebar-splitter {border-width: 0 1px!important; min-width: 4px!important; max-width: 4px!important;}