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!