In my item list, if I turn off every single field (e.g., From, Subject, Status), there's still a small column all the way on the left with no identifier.

I've attached a photo with a red arrow pointing to the column in question.

The column seems to serve no purpose other than taking up space. I can't identify it, so I can't turn it off. Can someone help? Every inch counts on my screen.

Thanks!

Running Outlook 2011 on OS X 10.9.5; Office is up to date