protected override void OnDragEnter(F.DragEventArgs e) {
var wp = new DataObject.Win32Point() { X = e.X, Y = e.Y };
Drag_SetEffect(e);
if (e.Data.GetDataPresent("DragImageBits"))
DropTarget.Create.DragEnter(this.Handle, (System.Runtime.InteropServices.ComTypes.IDataObject)e.Data, ref wp, (Int32)e.Effect);
else
base.OnDragEnter(e);
}