Delphi Seattle DataSnap Client - Proxy server settings not working

Due to a bug in the Datasnap.DSHTTPClient.pas unit, the TDSHTTP.PrepareRequest procedure only applies proxy server settings when a proxy username is specified.

procedure TDSHTTP.PrepareRequest(const ARequest: IHTTPRequest);
var
  LIPRequest: TIPHTTPRequest;
  I: Integer;
  Lprox: TProxySettings;
begin
  if FProxyConnectionInfo <> nil then
  begin
    Lprox := TIPProxyConnectionInfo(FProxyConnectionInfo).FProxySettings;
    //if Lprox.UserName <> emptystr then  // <-- Comment this line out
      FHTTPClient.ProxySettings := TProxySettings.Create(Lprox.Host, Lprox.Port, Lprox.UserName, Lprox.password, Lprox.Scheme);
  end;

To resolve the issue, this line should be commented out:

//if Lprox.UserName <> emptystr then  // <-- Comment this line out