>just wondering, can you set relationship between tables with grid-in-grid method?

The one I built had the customer table in the outer most grid, with the orders table in the contained grid and the third grid was the line items table for the orders. The relationships were handled by the Data environment, but could have been done using the grid's properties.

The triple grid blows up regularly, it loses track of record pointers and shows bogus data at times. It really is a curiosity only and should never be done in a real system. Why not, first it is confusing to use, second it is very fragile and blows up frequently, third the grid is complex enough without us making it more so.