DataGrid._onSet does not handle change in item identity

[fgamador]

If the identity attribute of an item in the datastore changes, DataGrid? should update its internal index (i.e. this._by_idty), but it does not. I ran into this because I allow the user to create new objects by adding rows to the grid. The items for those rows are given a temporary identity. When the user saves their changes, the items get new identities from the server. However, DataGrid? still indexes them under their old identities, which causes problems.

[Nathan Toone]

You can't change the identity value of an item in a store. That is explicitly disallowed by the dojo.data API.