Xcode : shortcut for highlight feature

Question

I recently started using Xcode for developing. It's pretty neat. By accident I happened to see one of its features. The feature only highlights the block of code I am currently working on. Other codes are covered with light grey. I do not know how to get that effect again. Can anybody help? Thanks!

Answer 1

You probably hovered your mouse over the line number bar like this:

Answer 2

You may be referring to the "focus ribbon" on the left side between the code and line numbers.

Refer to: https://developer.apple.com/library/mac/#documentation/ToolsLanguages/Conceptual/Xcode4UserGuide/Editing/Editing.html

(Figure 3-10)

Answer 3

This is called Code Folding Focus.

If you want to turn it ON or OFF as you please, do as follows in Xcode/Preferences:

Then, assign the key of your fits.