I have a grid with several columns that I want to aggregate data from. Let's say that the grid contains columns filled with numbers. The rightmost column should view the sum of all the numbers on the left. What I did was to implement a custom ValueProvider for this column. In the getValue method I add all the numbers of the proxy and return the result.

The problem with this approach is that the grid is only updated live if I set the store in autocommit mode. The ValueProvider always works with the backend model, not the internal records of the grid. Because of this, the original value will be given to the ValueProvider when it should update the grid data. The modified value remains in the grid store only. Because I am in autocommit mode, I will never see the red corner mark on the modified cells. If I disable autocommit the values will of course be updated when I prepare the backend model for persisting it.

Is there a better way to solve this problem, or does this need changes to the library?