If you hover over on the lines, it will shows you a tooltip with the opening of that block and its parents. Structure Guide Lines.
To unindent a block one level , select it and press " Shift+Tab ". Indent Guides in Visual Studio 2010 (First posted on: 2012-05-14 11:09:20+00:00) Indent guides are vertical lines drawn by the editor to show the levels of indentation at each line of source code. When writing code, to indent an entire block of code one level without changing each line individually, simply select the block and press "Tab". Visual Studio 2017 introduced an interesting feature that draw a dotted structure guide lines on your code. Visual studio’s smart indenting does a pretty good job of automatically indenting code as it is written or pasted into the code editor. Indent Guides is a beautiful extension that adds this feature to Visual Studio 2010. It draw a dotted vertical line between the curly braces ({}) to identify the individual blocks easily. This can be quite useful to understand or edit code that has more than a handful levels of indentation.