Overview
In BlueSpice 4, an additional custom menu is integrated as a mega menu.
If the menu doesn't exist yet, you first have to create the following page: MediaWiki:CustomMenu/Header
If the menu exists, the link-icon is displayed. You can click on the Edit menu link to edit the links in this menu.

This menu can be created and edited by users with admin rights.
Menu editor
View instructions on the menu editor help page.
To remove the custom menu link-icon from the wiki, the MediaWiki:CustomMenu/Header
page must be deleted. The page can be restored via the deletion log.
Layout for many columns
If you're building a menu with many columns, the following CSS adjustment may be helpful. On the Flexiskin special page, enter the following CSS declarations in the "Free CSS" text area:
.navbar-nav .dropdown-menu {text-align:center;}
.mega-menu-wrapper.d-flex {padding-bottom:3rem; justify-content:start; gap:0 30px; max-width:1600px; margin:auto}
.card.card-mn {min-height:unset; padding:0; margin-top:1em}