Force Internet Explorer rendering engine

In many intranet settings Internet Explorer will fall back to the lowest possible version of the embedded rendering engine because the Flamingo services are in the "Intranet Zone", this is a built-in behaviour to make it easier for legacy applications to keep up with technological advances in that environment. However this will cripple parts of both the Flamingo viewer as well as the Flamingo viewer-admin (Flamingo tries to keep up with technological advancements).

To circumvent this problem a special host header needs to be set to switch on the up-to-date Internet Explorer rendering engine, for Apache add the following header to the virtual host: Header set X-UA-Compatible "IE=Edge", for nginx use add_header X-UA-Compatible "IE=Edge" for iis add a custom header like <add name="X-UA-Compatible" value="IE=Edge" /> to the web.config. If running in a standalone servlet engine like Tomcat you can add a rewrite filter, see: https://stackoverflow.com/questions/2810271/configure-tomcat-to-send-web-pages-compatible-to-ie-7-or-6

see also: https://github.com/flamingo-geocms/flamingo/issues/630