Yeah, it's probably not going to work. I had filed a bug report with MS and this is what they said:
The JScript IntelliSense relies on successful execution of the script (in this case Ext) to provide IntelliSense. You would need to take a look at the line position described in the error to diagnose and get it working. Note that the mock execution we perform will not have all of the browser DOM objects available to it and this is a common point of failure. However, we've found that most libraries will about browser DOM interaction on initial load since it's not deterministic which elements will be available. We are working on more robust mechanisms next version.
The bug report I filed had this detail:
Steps to Reproduce
Download Ext from extjs.com, latest release version 1.1.1. Unzip and copy it into a subdirectory of a simple web app project. Include ext on an simple html page like this, adjusting the src paths to your path:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<link rel="stylesheet" type="text/css" href="js/ext111/resources/css/ext-all.css">
<script type="text/javascript" src="js/ext111/adapter/ext/ext-base.js"></script>
<script type="text/javascript" src="js/ext111/ext-all-debug.js"></script>
<title>Application Layout Tutorial</title>
</head>
<body>
<div id="hellodiv">
Hello there
</div>
<div id="btn1">button1 div here</div>
</body>
</html>
Then build the project and look in the ErrorList window.
Actual Results
Error updating JScript IntelliSense: <my path to Ext>\adapter\ext\ext-base.js: Object doesn't support this property or method @ 9:7310