FIX.RadDropDownList - SelectedItem is reset to null when the Form.ShowDialog method returns OK in Excel AddIn and RadDropDownStyle.DropDown is applied
Please refer to the attached sample project. When you run it, there is a new ribbon tab in the Excel (tab2) and a new button (button1) to click.
Workaround:
this.radDropDownList1.DropDownStyle = Telerik.WinControls.RadDropDownStyle.DropDownList;