css dropdown menu problems

after reading eric meyers article on using the hover to create popup menus I am having some problems. I can get things to popup but if I use absolute postioning, all the popup menu options overoverlap eachother, where as if I use relative positioning the don't overlap, but they then cause all the other menu options that lie below the selected menu option to shift down to make room for the hidden menu options. I hope I am clear

Here is the css, pretty simple, but I can't figure out how to make things work right.


#LeftSideBar span .Sub{
display: none;
}
#LeftSideBar span:hover .Sub{
display: block;
position: relative;
left: -4em;
}