Weird toolbar in Aperture

Hello everyone.

Today i noticed a strange toolbar in the bottom part of the Aperture window, that I haven't seen before.
It is quite annoying, since it takes up screen real estate, and I can't use it for anything.

Do one of you guys know how to remove it again?

I have attached a screen cap, so you can see what I'm talking about.

Thank you in advance!

Thank you for the answers, both of you!

When it comes to key wording, I guess that I should get started with it. I would probably thank myself in the long run!