WP 4.8.1 Visual Editor and IE11 compatibility issue

Hi all

I have come across an issue with WP 4.8.1 Visual Editor and IE11 which a number of our users have just noticed. The VE does not appear, only the text editor, with no tab options to switch between the two.

A little background first…

I manage a large number of WP site for our organisations and other customers.
Most of our organisation sites are all based on subdomains of our primary domain; e.g. subsite.domain.com.

The websites that are affected are all on a subdomain of our primary domain and are on WP 4.8.1.

I have verified that other sites not running on our domain are ok.

In addition one other site running on a subdomain of our domain does function correctly but this is on WP 4.7.5.

Possible Cause

The obvious reasons this is happening is this that while we are logged into our organisation domain and the sites running under our subdomains will trigger IE11s compatibility mode.

Internal domains are seen by IE as ‘Intranet’ and this triggers compatibility mode.
To verify this we accesses the sites from outside of our domain and the editor works correctly.

Each of the sites we include the force IE=EDGE trigger via some script in the .htaccess at the site root – i.e.

<FilesMatch "\.(htm|html|php)$">
	<IfModule mod_headers.c>
		Header set X-UA-Compatible "IE=Edge,chrome=1"
	</IfModule>
</FilesMatch>

This usually solves these sorts of IE issues, at least at the front-end of the website. Also as I mentioned there is no issue with WP 4.7.5.

We cannot change the IE default for Intranets as some other site we run internally do require this functionality. Plus our group policies on the network disable access to manage this feature for the majority of individuals.

Actions so far…

Via the developer console in IE11 I have verified that site “is running in Compatibility View because ‘Display intranet sites in Compatibility View’ is checked”.

But the Document mode is IE11 “via X-UA-compatible HTTP header”, and user agent string is IE11 also.

Other than that there are no errors in console.

I have done the usual actions such as disabling plugins and clearing browser caches.

I have even added additional .htaccess files with the IE=Edge header script at different levels within the wp-admin folder but to no avail.

Has something changed recently in WP 4.8 which ignore the whole “via X-UA-compatible HTTP header” setup and just check for compatibility trigger to affect changes?

Any suggestions?

• This topic was modified 7 years, 6 months ago by Castor.