Because it is necessary to click a list item to produce the submenu I said that it was not possible using CSS as you cannot have a click followed by another click (all the second click would do is cancel the first click).
However, after playing around with the idea for some time, I have found a way to use hover on the main menu to produce the submenu which can then be clicked.
This does require that all the sublevel lists are the same height irrespective of the number of submenu items. If they were different heights than the top level items would jump around with no control as each top level was selected.
So this is the most basic of menus to show the principle. No doubt it can be refined and styled further, but for now this is it.
It works in IE6, Firefox 22.214.171.124, Opera 9, can be made to work in IE5.5 with a couple of hacks.
Oh....and it stays in shape no matter what font size is selected.
Because of all the time and effort spent in producing this demonstration I would ask that you respect my copyright.
This demonstration can be used subject to the following terms and conditions.
Your donations keep CSS PLAY running.
If your donation is for the use of a demo then please email me with the demo url after making your donation.