Zoiper’s Missing User Interface Labels

I have been trying to set some advanced options in a Zoiper Biz 3.13 account but I could not find four options that are described in the Help (Use DTMF, Transport, SRTP, and STUN).

Finally I realized that these are unlabeled drop-downs. Although the UI design makes it look like the four checkboxes on the left control the four drop-downs to their right, this is not the case. Here is the UI with the missing labels: