Allow sites to be reloaded in Internet Explorer mode Greyed Out

Stipe06 

To enable "Allow sites to be reloaded in Internet Explorer mode" on managed devices (version 86 and above), either

• enable it in GPO settings under "Administrative Templates/Microsoft Edge/Allow Internet Explorer mode testing"
• or go to registry "HKEY LOCAL MACHINE\SOFTWARE\Policies\Microsoft\Edge" and create a REG-DWORD with the name "InternetExplorerIntegrationTestingAllowed" and set its value to 0x00000001

After a log-off the option to open sites in IE Mode is available in the menu under "More tools", although it's still greyed out on the settings page. 

Afaik the background behind is that MS assumes that organizations with managed devices don't want to allow users to open any site in IE Mode due to security reasons and therefore control the access via IE site lists.