Pop-up 'bottom-end' instead of opposite?

[Chaddeus]

I'm working on a menu in an app, that appears when a user pauses typing. It's working very well right now, but when the user's text is near the edge of the canvas, Tippy is flipping the position from 'right-start' to 'left-start' (opposite) -- but there doesn't appear to be a way to change the behavior.

Unless I'm mistaken. Is there a way to set Tippy to use something like 'bottom-start' if 'right-start' is off canvas?