Hi,
In the DropDownFormCellRenderer''s OnButtonClicked, if you set the value string to both Style.Text and ControlText it will solve the issue. I have attached the sample.
Sample
this.Grid.Model[rowIndex, colIndex].Text = this.ddForm.GetValuesToString();
this.Grid.CurrentCell.Renderer.ControlText = this.ddForm.GetValuesToString();
Regards,
Calvin.