"Content" / "Create content" menu items broken when "Create content" menu item moved

Hi,

I have a bad problem with drupal and think this is a bug.
I don't know exactly what I did, I'll try to give my best to explain.

With no additional modules enabled, I changed the structure of my Navigation menu, so that "Create content" is NOT a submenu of Content any more.
When I now add a new Content Type "testpage", Drupal does it, but puts the new menu item directly into the root of the navigation menu - it SHOULD put it under Content->Create content->Test Page.
Additionally it creates a new menu item "Create Content", directly in "Navigation" as well.
So ATM I have 4 "Create Content" menu items, and neither of them can be deleted (I can only "disable" them to make them invisible).

I have attached the menu page as html file, so you can see the items.
The first checkbox has the id "edit-mlid:11-hidden".
the others have edit-mlid:113-hidden, edit-mlid:228-hidden etc.
So I think the first one is the real one, but can not be further resetted.
The others are boguses, , I can't delete them any more.
Normally you should be able to reset the menus to their original state. But I did that with all of the items - and it didn't help.