I just rolled my own for the special purpose I needed within my xblock - not something you'd want to do site-wide. I suspect that it has something to do with the "use strict" mode that the tooltip code uses. Studio and LMS load javascript into the page in a very different way than workbench does....(and in your case, perhaps
edx.org does this also).... and the "use strict" creates a problem with scoping.
Anyways... my immediate problem is solved.