How to make sub-menus fly out to the left

We’ve got a sub-menu (level 2) of a sub-menu (level 3) and it’s positioned in such a way that the items in the level 3 menu are off-screen. I’m attaching a screen grab to illustrate the issue. Is there any way to force that level 2 and level 3 menus to appear to the left (i.e., on-screen) instead of it defaulting to the right, short of moving the level 1 item to a position farther to the left?