NullReferenceException when entering the cell in edit mode, then refreshing the data, then enter the cell in edit mode and pressing the Enter key

Provide a RowStyleSelector property to the DataGrid control.

When a ComboBox editor is open in the DataGrid, one can use the arrow keys to go up and down the items of the combo in order to make a selection. When pressing Enter it is expected that the ComboBox gets closed and the DataGrid is still in edit mode for the same cell.

However, when the Enter is pressed - the ComboBox closes and the next row goes into edit mode - this behavior is erroneous.

When grouping in the DataGrid, add an option to align aggregates in group header based on the columns they are applicable