Append row to group in Table View

Hello John.
Thank you for your message. This is how standard VCL datasets operate- the Insert method inserts new records BEFORE the focused record. ExpressQuantumGrid simply inherits this behavior.
To work around this behavior, you can focus the next record and then insert the new record manually. As a result, the inserted record will be placed below the focused one.
In the attachment, you will find an example that demonstrates this approach when the Navigator's "Insert" button is pressed. We look forward to your feedback once you have had the opportunity to try our solution.
Best regards,
Ingvar.

I'm sorry but the example project that you posted does not implement the desired behavior. The newly inserted row should the the LAST ROW in the current group. Your example places the new row below the current record. After several hours of trial and error, I came up with this solution to implement what should be a baseline feature.
function FocusNextRow(AView : TcxGridDBTableView; StayInGroup : boolean = False) : boolean;
begin
  //Expand if on group row and jump to first data record of group
  if AView.Controller.FocusedRecord is TcxGridGroupRow then begin
    AView.Controller.FocusedRecord.Expand(True);
    AView.Controller.FocusedRecordIndex := AView.Controller.FocusedRecordIndex +
      AView.GroupedItemCount - AView.Controller.FocusedRecord.Level;
  end else begin
    //don't append row if on last row
    if AView.Controller.FocusedRecordIndex<AView.DataController.RowCount-1 then
      //Focus next data record
      Result := AView.Controller.GoToNext(True)
    else
      Result := False;
    //Expand if on group row and jump to first data record of group
    if AView.Controller.FocusedRecord is TcxGridGroupRow then
      if StayInGroup then begin
        AView.Controller.GoToPrev(True);
        Result := False;
      end else begin
        AView.Controller.FocusedRecord.Expand(True);
        AView.Controller.FocusedRecordIndex := AView.Controller.FocusedRecordIndex +
          AView.GroupedItemCount - AView.Controller.FocusedRecord.Level;
      end;
  end;
end;
procedure AppendRowToGroup(AView : TcxGridDBTableView);
var
  AValue : Variant;
begin
  with AView.DataController do begin
    Assert(AView.GroupedItemCount=1,'This only works if grouped by one column.');
    //Save current grouping value
    AValue := AView.Controller.FocusedRecord.Values[AView.GroupedColumns[0].Index];
    //Move to last row of group;
    while FocusNextRow(AView, True) do; //Don't wrap this in BeginUpdate…EndUpdate!!!
    BeginUpdate;
    //Move to next row in dataset
    if FocusedRecordIndex < RecordCount - 1 then begin
      FocusedRecordIndex := FocusedRecordIndex + 1;
      Insert;
    end else
      Append;
    SetEditValue(AView.GroupedColumns[0].Index, AValue, evsValue);
    Post(); //<-- Wish there was a way not to have to commit this record to Dataset yet
    EndUpdate;
  end;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
  AppendRowToGroup(cxGrid1DBTableView1);
  cxGrid1.SetFocus;
end;

Hello John.
Thank you for sharing your solution with us, which can be helpful for other customers with a similar task.
As for integrating this feature to our TcxGrid, you can post a separate suggestion to our Support Center. Our developers will consider it and possibly implement in future versions of our controls.
Please let me know if you need any additional clarification.
Best regards,
Ingvar.