setup app broken in IE

This has been tested using a virtual machine, connecting to an Essentials webapp running on the host. I recommend re-testing this on a native Windows machine. Having said that, Chrome in the virtual machine worked just ok ...

Problems found:

• After installing a feature, and then stopping Tomcat, IE does not display the "webapp is rebuilding" message
• After restarting Tomcat, and refreshing IE, it does not update it's list of installed plugins. You can reload the page, but the list will not be updated ... when you clear the browser cache, you'll see the updated list.