How can I enable X-UA-Compatible meta tag in Edge Chromium with IE Mode?

Question

I have an ASP.NET Web Forms website that works in Edge Chromium with IE Mode. To distribute the IE Mode website enablement to the domain user I have defined a Group Policy and a XML site list file with the Enterprise Mode Site List Manager. The site list file is like the following:

  <created-by>
    <tool>EMIESiteListManager</tool>
    <version>12.0.0.0</version>
    <date-created>25/04/2022 16:35:57</date-created>
  </created-by>
  <site url="myintranetdomain.com">
    <compat-mode>IE8Enterprise</compat-mode>
    <open-in>IE11</open-in>
  </site>
</site-list> 

Most of the website pages work without problems, but some pages need to be executed with the “X-UA-Compatible” meta tag:

<meta http-equiv="X-UA-Compatible" content="IE=Edge" />

If I enable the Edge IE Mode manually this meta tag is processed and these pages work fine. But if I define the site in Enterprise Mode Site List file this meta tag is ignored. This behavior is illustrated in the Microsoft documentation too. Is there any way to distribute the Edge IE Mode site enablement to many user without the Enterprise Mode Site List file or is there another way to define the Site List file? I have tried all the values of “<compat-mode>” and “<open-in>” in the Site List file but it doesn’t work.

Answer 1

I have found the solution executing other tests with the Enterprise Mode Site List file. To allow the functioning in IE Mode enabled via Group Policy of both the pages types (with and without the X-UA-Compatible meta tag) the <compat-mode> must be set to "Default". So the Enterprise Mode Site List file will be like the following:

<site-list version="2">
  <created-by>
    <tool>EMIESiteListManager</tool>
    <version>12.0.0.0</version>
    <date-created>29/04/2022 22:16:46</date-created>
  </created-by>
  <site url="myintranetdomain.com">
    <compat-mode>Default</compat-mode>
    <open-in>IE11</open-in>
  </site>
</site-list>