IE display problems: forms and nav menu

[Cyclist]

I am using navigation with subitems on my site. Everything is displayed correctly in FF but in IE it makes problems when a form is used. Please see the attached images which demonstrate my problem in IE. In IE the navigation moves behind the form. Using different z-index doesn't change anything. So I wonder what's is causing this strange behaviour. This problem occurs everytime when the subitems should overlap a form, e.g. on the news (news form) and list page (page selector form). Apperently IE forces form items overlapping all other objects, ignoring any z-index.

I have no idea how to avoid this behaviour (bug?) in IE. Does anybody know how I could solve that problem?
Does the news overview has to be a form? Is there another working solution not using forms?

Thanks for your help in advance.

[Pekka]

It's CSS2 z-index value problem. Most browsers start z-index from 1, IE adds some offset so you need really big values to get things to top.

[Cyclist]

It's CSS2 z-index value problem. Most browsers start z-index from 1, IE adds some offset so you need really big values to get things to top.

I thought that first, too. But I tried values from 1000 to 100000000 as z-index for my drowdown menu. The problem persists. The z-index doesn't seem to have any effect on that. I can change it to whatever value it doesn't change anything. If you look around the web many people report about that issue.

If the news overview weren't using the form element I wouldn't have figured out that problem. It only occurs when using the dropdown menu together with forms.

[PrimaPhoto]

This may help?
http://thedesignsuperhero.com/2008/02/drop-down-menu-disappears-behind-select-box-in-ie6/