Bridge 13 scripting content tabs

I have a number of scripts that i have been using and work in previous versions of bridge. One of them uses two bridge windows. In the new version of bridge this is not possible they have now moved to content tabs. 

Does anyone know the syntax to selected files from different content tabs? It seems you can only have 1 document now. 

here is a snippet from an existing script which worked in previous versions of bridge

 var sel1 = app.documents[0].getSelection(); 
      var sel2 = app.documents[1].getSelection(); 
      if(sel1[0].core.itemContent.fileFormat == "Photoshop document")  {var main =  sel1; var layout =  sel2;}
      else{var main =  sel2; var layout =  sel1;}