>What's the exception?
Because EditItemIndex is somehow going from a non-negative number to -1 between the SaveDataSet Call and the mmDataGrid.BindBack method this line:
DataGridItem item = this.Items[this.EditItemIndex];
Is throwing this exception:
[Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index]
Rip Ryness
International Falls, MN