16.2.1 Dragging values from a choice

To implement dragging in list-panel or tree-view supply the :drag-callback initarg. When the user drags, drag-callback receives a list of indices of the choice items being dragged. The drag-callback should return a property list whose keys are the data formats (such as :string or :image ) to be dragged, along with the values associated with each format.

16.2.1.1 Example: dragging from a tree

CAPI User Guide (Macintosh version) - 30 Aug 2011