.ux-MultiSelect-icon { width:16px; height:16px; float:left; background-position: -1px -1px ! important; background-repeat:no-repeat ! important; }  
.ux-MultiSelect-icon-checked { background: transparent url(../images/default/menu/checked.gif); }  
.ux-MultiSelect-icon-unchecked { background: transparent url(../images/default/menu/unchecked.gif); }