Folder either shows empty page or 404

When I create a folder it shows up as a menu, as it should. But when a user clicks on it, it opens a blank page. When I disable routing it becomes a 404. How can I just create a menu item which doesn't link to anything? What I want to setup is that when someone clicks on it, it only expands the menu, nothing more.

At the moment I created page redirects to one of the folder items in order to hide this problem. But it's not pretty. Also the TNT Search has some problems with this, when I type in a keyword which is a redirected folder, the page deforms.

The dropdown menu feature is not, as far as I can tell, included in the core Grav code. It is implemented only if a theme includes it as an option. From my understanding, the Antimatter theme has it (off by default) but I am not sure about other themes.