How can I create Yosemite-style view with translucent/blurry background?

w00t! I’ve found example code that uses not-yet-documented view type:

1. Set XIB’s deployment target to 10.10
2. Embed your view in NSVisualEffectView
3. In Interface Builder’s settings for the view set appearance to “Vibrant Light/Dark”. There are other options, like blending “Behind Window” or “Within Window” (the latter requires layers).

There’s also NSView method allowsVibrancy that you can override to return YES, but for reasons I don’t yet understand this didn’t enable vibrancy in my case.