Shouldn't “X-UA-Compatible IE=edge” header override “Display intranet sites in Compatibility View” in IE10?

Question

I have a simple HTML5 / ASP.NET website that I started testing in IE10 today since it released for Win7.

This is an intranet site within my organization, and I believe awhile back there was a group policy deployed to enable the Display intranet sites in Compatibility View by default.

The thing I noticed today in testing was that even though I am adding an X-UA-Compatible IE=edge HTTP header (via my web.config), the site is showing in IE as:

Browser Mode: IE10 Compat View
Document Mode: Standards

I believe my HTML is actually OK though, because I can simply uncheck the Display intranet sites in Compatibility View setting and when it reloads, it immediately switches to:

Browser Mode: IE10
Document Mode: Standards

So my question is simply, shouldn't the IE=edge header value override the Display intranet sites in Compatibility View setting?

If not, is there any way I can override it?

Answer 1

(I'll put this here because this question ranked higher for my google search, but after more digging I actually found the answer on another SO question: https://stackoverflow.com/a/13287226/1563. I'm not sure if they should be merged (at least not without some question editing))

This is likely happening because IE is set to "Display intranet sites in Compatibility View" (Alt+T | Compatibility View settings)

You can't override this setting using the X-UA-Compatible meta tag but you can by sending the X-UA-Compatible http header:

X-UA-Compatible: IE=edge

Credit goes to Lavinski for finding this

Answer 2

This worked for me, try clearing existing headers before adding the new one or any others.

<httpProtocol>
    <customHeaders>
        <clear />
        <add name="X-UA-Compatible" value="IE=Edge" />
    </customHeaders>
</httpProtocol>

Answer 3

I believe X-UA-Compatible forces document mode while "Compatibility View" turns on both IE7 browser and document mode -> the document mode was actually overridden by X-UA-Compatible.

See Difference between "Browser Mode" and "Document Mode" in Internet Explorer