DataGrid

I have two DataGrids for Master and Detail. I enter data into the new record in Detail grid and, while it is not committed, click on another master record in the Master grid. When I return to the previous master record I see that the newly entered detail record has gone. I inherited from DataGridTextBoxColumn and used this new class for the column in the detail grid. When I click on another record in Master, DataGridTextBoxColumn''s Commit get called and I can see that CurrencyManager passed to it is wrong (corresponds to the clicked master record). Any ideads how to make it save the newly entered detail record?