I'm using the new Internet Explorer 11 developer tools to switch the document mode to "8", but conditional comments are still ignored, that is, they are not properly parsed and behave like normal comments. So any referenced file inside the conditional comment is not requested/loaded by the browser.
Why does this happen? Is it a bug?
If you think that this is indeed a bug that needs to be fixed, please go in and say that you too can reproduce this on the Microsoft bug report that is reported for this issue:
Conditional comments do not work when emulating document modes via F12 Developer Tools.
Update: This issue has been reported to be fixed in the mentioned bug report.