content: sub ShowGroupScreen()
      m.GroupScreen = CreateObject("roSGNode", "PhotoAppGroupGrid")
      m.GroupScreen.ObserveField("groupID", "OnGroupSelected")
      ShowScreen(m.GroupScreen)
  end sub
  
  sub ShowGridScreen(groupID as string)
      m.GridScreen = CreateObject("roSGNode", "PhotoGridScreen")
      ShowScreen(m.GridScreen)
      LoadGroupContent(groupID)
  end sub
  
  sub OnGroupSelected(event as Object)
      ShowGridScreen(m.GroupScreen.groupID)
  end sub