may I ask a few questions 1) (a suggestion) why do you need multiselect if jstree already support drag drop? http://www.jstree.com/documentation/dnd# and I didn't see a better way to manipulate hierarchical data than what it offers an alternative is nestedSortable http://mjsarfatti.com/sandbox/nestedSortable/ but when you want to move a node with a lot of children it has poor performance
2) (interested because I did research some time ago on that field) why did you chose closure data model? --
