The 'dragsource' property

Valid for: All visible controls

Read-only, character vector

The dragsource property is used in drag-and-drop operations. When a drag-and-drop callback occurs (i.e. one of onDragStart, onDragEnd, onDragOver, onDragEnter, onDragLeave, onDragDrop), the dragsource property contains the name of the control which is being dragged.