Hi there,
With reference to this thread:
http://forums.ni.com/ni/board/message?board.id=170&message.id=317640&requireLogin=False
Some of LabVIEW's features/functionality operates differently with the Touchpanel Module, or is not available. The above thread mentions about the behaviour of pop up subVIs, so this should help you with your question.
Regards,
Dan - NIUK