I am using Xcode Version 4.4.1 (4F1003) on OSX Mountain Lion 10.8.1
Say you are debugging in Xcode, and you stop at a breakpoint.
Then you go to the debug console prompt and start typing po loc...
For me, one of two things will happen:
1.) The console will display a popup with options (the same way autocomplete works in the main text editing window)
or
2.) The console will simply automatically autocomplete to the first thing it finds. For example po localeconv(). Even though I was going to type po locationForAPI.
As far as I can tell, it is random as to when Xcode will behave as 1 and when it will behave as 2.
It turns out that 2 is not very useful at all (here are people trying to turn this functionality off).
But, behavior 1 is very useful!
Thus, my question: Does anyone know how to force Xcode to use behavior 1 and not behavior 2?
Solution: Restart Xcode
Xcode always starts in the good behavior and then switches to the bad behavior at some point.
(The classic "Delete Derived Data" doesn't work in this situation)
来源：https://stackoverflow.com/questions/12220682/how-to-make-xcode-4-4-debug-console-use-a-popup-for-autocomplete