IIS7 Forcing IE7 Mode with no response header or web.config settings

We have one server that is forcing IE7 mode in IE8 and IE9. I've checked the HTTP Response Headers and we do not have an X-UA-compatible header set. Nor do we have customHeaders configured in our web.config. When we run our app on any developer's machine or on our development server IE8 and IE9 render our app in IE8 开发者_JAVA技巧and IE9 mode respectively.

Is there some other setting we're missing that could force IE7 mode?

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This is probably due to the "Display Intranet Sites in Compatibility View" setting, that is defaulted to on for IE. Go to Tools->Compaitbility View in IE on the developer machines and turn it off to see if that is the problem.