I’ve been using OSX Lion for three years now and I’ve never had any trouble connect it to any kinds of external display.
Now I get to try Mavericks Operating System (10.9.x) on another early 201 Mac Book Air (MBA). I didn’t face any trouble until I try to connect it to an LCD projector. I just realised there’s no display property icon on the menu bar.
I googled it, turns out that we have to set the icon manually on the menu bar. Next problem is, it has no “detect display” button. Apple for some reasons removes it casually on Mavericks. So it’s not a bug or virus.
You still can pop the button manually by pressing “option” button. The same thing if you want to change (increase or decrease) the screen resolution. Press “scale” button and hold the “option” button.
Not very practical from my personal opinion, but worth to live with. 🙂