Choose Photos to Share with Apple TV not working (blank window)

Hi, I'm using the new Yosemite Photos and want to share some Albums to my Apple TV.

When I choose File>Home Sharing>Choose Photos to Share with Apple TV it opens a "Photo Sharing Preferences" window but its blank with the buttons "Revert" and "Apply" greyed out.

What can I do if there's nothing to select or change in this window?

I'm using iTunes 12.1.2.27 with Yosemite 10.10.3

Thank you!

Robinson