Issue with code autocompletion / syntax highlighting in Xcode 4.x

Question

I am having a rather strange issue in Xcode on one of my projects.

When I start to write my code, I am used to the auto-completion suggesting numerous entries for me

Answer 1

Its really embarrassing. By mistake I took off the Check mark in the Xcode Preferences> Text Editing> Code Completion and I tried every possible solution of that.

Please check this preference also before digging into any other solution: