Display method in AxGridView in EP

hi,

 I have datasets with two data source: SalesBasket - SalesBasketLine (relation: innej join). In Datasource SalesBasketLine I have simple method itemId.

display ItemId itemId()
{
    ;
    return salesBasketLine.ItemId;

}

I used this method in axGridView in Enterprise Portal. The problem is that I got in all rows the same value from the first row.

Why? This bug?