Kamil,
>I had similar elusive behavior conserning RV with table buffering. Add to this a grid and a couple of relations and you get an upredictable mixture. I decided to stop groping my way to the end of the project and create an artificial table buffering which consists of a RV with the record buffering and a copy-cat cursor where in fact you do all the changes, then save them to RV, to SQL server.

We already changed the way we do deletions in grid. We added a logical column in updatable RV and displayed in the grid as Marker. The default is true whenever insert is done but if the user decided not to include any row in the grid, it must be ticked as false so that it will be bypassed if computation is made. At save event, we delete all rows marked as false then tableupdate. This is something similar to some web pages I see including hotmail.