Outlook Web App Functionality Disabled

Scenario: When a user is in Outlook Web App (OWA), they may be experiencing one of the following issues:
  • Conversations are not being expanded.
  • Composing new or replying to messages is not possible due to the body or other parts of the message being disabled or greyed out.
Resolution: There was a DivX Plug Web Player HTML5 add-on in Internet Explorer that I had to disable. To disable this add-on, click on Tools-->Manage add-ons.
Troubleshooting Note: There may be other add-ons causing this issue as well where you might have to perform process of elimination with disabling/re-enabling add-on's.