Structural Highlighting shows how your code lines up.
The feature is most useful if you are working with a code block that can not be fully displayed on the screen at once.
By default, this feature is enabled. You can disable it or customize the highlighting settings within the Structural Highlighting options page.
This product is designed for outdated versions of Visual Studio. Although Visual Studio 2015 is supported, consider using the CodeRush extension with Visual Studio 2015 or higher.