Intermediate Menu Items do not show linked content

Sorry for the late reply. We are using Joomla 2.5.4.

try to use an "external url" type and set it with "javascript:void(0)"

Using an "external url" with "javascript.voi(0)" or "javascript.void(0);" has the same effect as using the "separator" type menu item. When I do so, the link is shown as "javascript.void(0);", but the submenu does not collapse, apparently.

give me your url to see the issue

The URL is dmv.mathematik.de/j25/
Problem occurs with the Menu items "Aktivitäten" (which is an "external URL" with "javascript.void(0)") and "Studium und Beruf" (which is a "separator" item).
Thanks for looking into this issue so closely!

the problem is taht you have a JS error in your page

TypeError: container is null
dmv.mathematik.de/j25/templates/beez_20/...t/md_stylechanger.js
Line 66

you must fix this