Sub menu items always visible


I use (not only on mobile) a modal to show my menu.
It would be nice if I could say that when opening the modal thus showing the menu that there was an option to set the sub menu items visible, without clicking on the main menu item.

I want my modal (menu) be opened like this:

And not like this:

As far as I know this is not yet possible.

Thanks in advanced and keep up the brilliant work!