RightClick FCPX Icon in Dock

So I never noticed this before. Is it a Yosemite thing? I just happened to right click the FCPX icon in the dock just now and a small list of libraries came up. I clicked on the one I want and Presto!

Was this here before?

Yes. It's worked that way in Mavericks for some time.

Also, if you hold Command+Option when launching, it offers you the ability to trash your preference files. And if you just hold only Command, it will bring up a window allowing you to chose which Library to open (only opening that one, not any others).

Then there's the thing where if you are wearing red shoes, and click your heels three times while launching FCPX, it will... wait, that's a beta thing, I can't tell you.