When adding new row, before finishing it - leave the grid focus (click a button outside the grid for example). The new row has been added but RowValidating event does not thrown.

Add similar like DateColumn.DateTimeMode property for GridViewDateTimeColumn. Link in MSDN: http://msdn.microsoft.com/en-us/library/system.data.datacolumn.datetimemode.aspx

When you have a parent-child relation in GridView and try to add a new row in the datasource programmatically, the new row does not appear in the child table. Note: At the first time the row is shown. If you try to add second new row, it does not appear in the grid.