Sprite Packer is greyed out. How can i enable it?

Hello!

I have Unity Pro and installed Unity 5 beta today.
When i go to “Window” the “Sprite Packer” is greyed out although it’s enabled in the Editor-Settings.

Anybody got the same problem?
Am i missing something here?

thanks in advance!

Me too. Just bought Unity Pro and this is still greyed out. What gives?