TinyMCE editor has focus issues in IE11

Steps to reproduce

Steps to reproduce

1. Create a new page - open the page in All Properities mode
2. Add something in xhtml editor
3. Open the publish menu, the content should autosave, hover one of the menu options so that it gets focus
   
4. Add more text in xhtml editor
5. See that no autosave happens
   

Expected:
Content is autosaved after focus is set somewhere else and then back into the TinyMCE editor

Actual:

Content is not autosaved