So, code blocks (which can be collapsed like #region blocks) have corresponding markers (+ symbols) to the left of the text editor. These markers should be placed right where the code block starts. My problem is that they are shifted upwards a bit.
Here is a screenshot in case I didn't explain the issue clearly enough: http://img191.imageshack.us/img191/3489/04071173010.jpg
upd: This behavior was caused by an extension (thx Nija). In my case it was Presentation Zoom. However disabling and enabling it again fixed the problem.
Thanks for help!
Try deselecting automatic outlining mode by going to Tools > Options > Text Editor > C# > Advanced and unchecking "Enter outlining mode when files open".
Restart Visual Studio.
If that doesn't work, try installing the Productivity Power Tools addon, which add more flexibility to the existing Visual Studio features and may correct your outlining.
If all else fails you might have to do an uninstall / repair.