Attach Browser 'iexplore.exe ACME': Invalid selector: <wnd app='iexplore.exe' cls='IEFrame' title='ACME System 1 - Work Items - Internet Explorer' />. Expected a <html> selector. Please make sure that you indicate a browser tab element

Yes, this is of course after I have added an Open Browser activity, specifying the URL and BrowserType, and then adding the Attach Browser activity inside the Open Browser activity.