I think I understand what you're asking...
Use a different menu for mobile. In that menu, create a parent menu item with a target url of #. When that parent item is clicked on, it'll expand without navigating to another page.
I have following https://community.getbeans.io/discussion/offcanvas-menu/ it's work like you say but after apply this feauture, parent element in menu misses link property. In other mobile menus, the arrow right links opens the submenu, this is possible ?
ok - I have this same problem. tried the # doesnt seem to be working.