HTML Editor not working

Hello,

We have a client with Windows 7 SP1 and I.E 11 and the HTML editor does not display properly in the Windows Client (version 9.40). 

Is there anything I can check? The support matrix simply says the below, which they do

"Note: For the HTML Editor to work correctly in the Windows client, the client machine must have a version of Internet Explorer installed that is supported for the web client."

Thanks,

Cory