Thanks OlegK
If I separate grid keys – it is fine, but:
1) These are separate grids, so there should be no connection between
2) I don't need to specify key.
3) If the Id's are the same for both grids – problem exists (look at current example code), I've left three same ids and one different 222
This means that it works fine unless parent grid Id is different than subgrid.
Probably workaround is to add extra column that will be a key. It would be constructed from SubgridId + id (I think that in one of versions it was like that).
Tomek