property Tree.OLEDropMode as exOLEDropModeEnum
Returns or sets how a target component handles drop operations

exOLEDropModeEnum An exOLEDropModeEnum expression that indicates the OLE Drag and Drop mode.
In the /NET Assembly, you have to use the AllowDrop property as explained here: By default, the OLEDropMode property is exOLEDropNone. The control provides the following options to define the visual effect when drag and drop items:

All options, excepts the exDragDropForeColor option accept skins. Use the Appearance.Add method to define new skins in the control.

Currently, the ExTree control supports only manual OLE Drag and Drop operation. See the OLEStartDrag and OLEDragDrop events for more details about implementing drag and drop operations into the ExTree control.