Target works when logged in but not when...not logged in

Target works when logged in but not when...not logged in

Hi,

I've a form in my app that reloads two frames upon submission - ie

  1.     rec  =  Performance_information  [ID == input.recordID];
  2.     newfurl = "https://creator.zoho.com/rsoftley/ast/form-perma/Performance_information/zc_Header=true&zc_SubmitVal=Add&zc_ResetVal=Clear&Venue=" + rec.Venue;
  3.     openUrl(newfurl, "iframe", "formFrame");
  4.     newurl = "https://creator.zoho.com/rsoftley/ast/view-perma/Performance_information_View/Venue=" + rec.Venue;
  5.     openUrl(newurl, "iframe", "frameName");
This works fine when I'm logged in but when I'm not - the app being public - the second page opens in a new tab.

To further confuse, another form in my app does EXACTLY the same thing and works fine, whether logged in or not.

???

Robert