airplay doesn't appear in MacBookPro5,4 running OS X 10.9.4
I updated my wife's MacBook Pro model MacBookPro5,4 to OS X 10.9.4 today, preparing it to (hopefully) mirror to an Apple TV 3 via AirPlay. The airprint icon does NOT appear in the menu bar.
It does appear in the menu bar of my MacBook Air (2013), also running OS X 10.9.4, and I've been able to mirror that machine through the Apple TV 3.
Why isn't AirPlay selectable with the MacBook Pro 5,4?
MacBook Pro, Mac OS X (10.6.6), iPod Classic 80GB A1238