Pop FIRST Window
[width (w)=500, height (h)=200, location (url)=SignInWindow.htm, passed variable (v)='firstpopup']

Pop SECOND Window
[width (w)=400, height (h)=200, location (url)=SignInWindow.htm], passed variable (v)='secondpopup']

Click above and popup will activate with the respective settings.

Once popup opens you can close the window by pressing "Close and Refresh Parent" button contained within the popup window.