procedure TForm1.ImageEnView1DragOver(Sender, Source: TObject; X, Y: Integer; State: TDragState; var Accept: Boolean);
// while dragging the ImageEnFolderMView1 image over ImageEnView1
begin
  if (Source is TImageEnFolderMView) then // if the dragged image comes from ImageEnFolderMView1
    Accept := True      // drag-drop cursor is shown
  else Accept := False; // not-accepted cursor is shown
end;