Horizontal Menu - set side for submenu to appear on?

We're using the Horizontal Menu object to make a two-tiered project menu, such as:

This works fine, but I'm trying to set up a mobile friendly version using breakpoints, which hides some of that extra information, and has the menu at the far top right of the screen. This means that when a submenu is opened to the right of the menu, it disappears off the side of the screen and the user has to scroll to find it.

Is there a way to (ideally) make the menu detect where it is in relation to the edge of the screen and appear on the best side, or (less ideally), be able to specify which side the sub-menu pops out on?