Example

Use a Custom Button to make the second radio button on the dialog enabled.

procedure TfrmMain.JSDialog1ControlClick(Sender: TObject; ControlType: TControlType; Control: TControl;
  const Value: Integer; var Handled: Boolean);
begin
  if ControlType = ctCommandLink then
  begin
    // Enable the second radio button in the dialog
    TJSDialog(Sender).EnableRadioButton(BASE_RADIOBUTTON + 1, True);
    Handled := True;
  end;
end;