Are handlers re-entrant?

I'm using Meteor and Spacebars (a variant on Handlebars), a dynamic templating system which redraws elements on the page when they change. It seems like the first time I call the code to set a drop target, when the page has been rendered and the dom is stable, everything works. However on the next pass, when it re-renders the page, it calls the setup code again.

This seems to remove the previous handlers for the drop targets, and they become non-responsive. They no longer target, show any indication of being a drop target or respond to drops.

Dragging still works.

I tried removing the sortable from found elements before I add it again on re-render, but it changes nothing.

Ideas?