HTML Editior tool bar not working in native IE 11, but works in Compatiblity mode

Hi Experts,
              We are working on SAP EP 7.3 sp 11.

        We have created some iviews using KM templates(fig.1). when we try to edit the form we get a screen with HTML editor(fig.2) to write comments and save all buttons except the tool bar (B,I,U etc) doesn't work but when we switch to compatibility mode it works properly.

This issue we are facing in IE 11 for other IE versions below  its working fine in native mode. Kindly suggest as we cant tell the users to switch to compatiblity mode always.

We went through the below notes where it tells to add <meta http-equiv="X-UA-Compatible"content="IE=EDGE"> but where do we add this so that it affects the complete Portal environment.

1)  1753544 - Web Dynpro - HTML standards mode

2)  1970689 - Use of "Edge" and "Compatibility" mode for Unified
Rendering 

When we click on "Supplier Announcements" form

HTML editor Property:

Thanks in Advance.

Regards,
Prajakta K