Need to use IE and MSOffice installed:
1. Upload an office document (.doc, .xls, .ppt, etc)
2. Click 'Edit Document Online'
3. Enter credentials inside Office
4. Make some changes and save. Close Office.
5. Notice browser still shows that the file is unlocked, so the only options available is 'checkout'
Page should automatically refresh so user can see the 'checkin' option.