- (void)endDragAt:(NSPoint)screenPoint
operation:(NSDragOperation)operation;
-// Drag moved; hook up to -draggedImage:movedTo:.
-- (void)moveDragTo:(NSPoint)screenPoint;
-
// Call to drag a promised file to the given path (should be called before
// -endDragAt:...); hook up to -namesOfPromisedFilesDroppedAtDestination:.
// Returns the file name (not including path) of the file deposited (or which