issuue with expanded row in ui grid getting refreshed on scroll, added dynamic rows to grid

i have injected some extra rows to grid dynamicaaly to create grouping title for names like A apple ample ama B ben bell where each row is expanding except title rows -- when i have expanded the rows and scroll the grid it refreshes the grid data again and my values in expanded rows gets reset , which is also creating scroll issue in mobile versiona and data reset issue, please help me i need help urgently

http://plnkr.co/edit/c74CeE7mAB6w7oGnuht0 attached the plunker ... code is there but plunker currently not working