Difficulty using revamped position utility with multiselect widget

Difficulty using revamped position utility with multiselect widget

I'm using Eric Hynds Multiselect Widget, but I'm having trouble getting the position option in the widget to work with jquery-1.8.2 and/or jquery-ui-1.9.1.

I believe that recent changes to the position utility are preventing it from currently working and I would love some help figuring out how to fix this issue. The working demo of the widget's position option is located here, but that uses jQuery 1.4.4, and more recent versions of jQuery prevent the multiselect elements from opening.