IE / VBA UserForm WebBrowser Control - Pop-Up Problem

<select name="status1" id="status1" onchange=";
                                checkReqStatus('1','MAILED','MAILED',form.statusHidden1,form.status1,'I','N','K','8',' ',' ',' ','N',' ','G',' ',roleArray,'false');
                                checkADGandAPS(' MAILED',form.statusHidden1,form.status1,'G','null');checkAgeOrdAPSForADG('MAILED',form.statusHidden1,form.status1,'G','false','');fnDrivingPHIOrder(this,'1','MAILED');
                              return checkRejStatus('1','MAILED',form.statusHidden1,form.status1,'null','N');"> 

I am trying to review some requirements, in the VBA userform web browser control. I load a webpage where there is a combobox dropdown that executes an onchange event, that will produce a popup with 2 user input fields and insert text into corresponding fields on the page.

In the userform, When I force the onchange event to occur by changing the default field, a popup shows up, but it asks me to login to the system (already authenticated in via userform browser control). I suppose that the popup doesnt originate from the web browser control, and is opening from the wrong instance. Im curious if theres a way to keep that functionality? It works correctly in stand-alone IE