Could Not Edit Rich Text Case Events in IE11

Error:

Mouse or text events freezes during editing case events in IE11 browser.

Audience:

Customer

Root Cause:

NA

Steps to Reproduce:

1. Log in to Manuscript
2. Open a case
3. Click the pencil to edit a case event (flip to rich text if necessary)
4. Click Cancel to stop making the edit
5. Try to type in search bar or select text on case

Workaround/Fix:

1. Click "Edit" for case and then click "Cancel" seems that approach closes all of the CKEditor properly.
2. Open CKEditor with case edit before editing any case events.
3. Use another Browser Like Chrome / Firefox.