In Xcode 3.2.1 I have this problem where it stops highlighting Objects in purple, and such. For example:
In that example, NSAutoreleasePool, pool, img, size, width and height should be highlighted, however, they are not. Here is a screenshot of what that looks like.
Anyone know how to fix this?
Edit: Also, code sense isn't showing correct options.
Xcode is often glitchy for me in similar ways. Restarting xcode often clears up the issue. Also, sometimes a missing semi-colon or curly brace will keep codeSense and highlighting from working as you want it to. Try Opt-B (build) to see if you have any errors that could be causing this.
I noticed that opening projects from the XCode welcome screen causes this issue. If I dismis the welcome screen and then go file open (or file open recent) and open the project that way the syntax highlighting works
来源：https://stackoverflow.com/questions/2263994/problems-with-xcode-syntax-highlighting