footer menu sub-menu collapse?

Hi there,

Unfortunately there isn't anything default that will build something like that.

I believe it will require quite a bit of custom coding as well.

The submenu is currently inline because of this CSS you've added though:

.footer-widgets .widget_nav_menu li {
    float: left;
    margin-right: 15px;
}

Otherwise they should stack on top of each other.

Let me know if this helps :)

yes i know. I dont want it to stack on top of each other. Oke thats unfortunately. I prefer a small footer menu where the submenu can collapse when clicking on it (just like a main navigation menu).

On a second thought, you could try Tom's suggestion here using the secondary navigation if you aren't already using it:
https://generatepress.com/forums/topic/secondary-menu-below-the-whole-page/