Mist simulator works as expected on our end, if you have a strict security policy at place, but obviously need to use our Mist client to develop, please ask your administrators to whitelist *.icenium.com to avoid such problems. If you want to pinpoint what is the culprit, try running FiddlerCap and look at its traffic, you might also check Chrome's Developer Tools/JS Console in case it reports any problems.
the Telerik team
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