The preview Window in Options -> Editor -> Formatting is quite useful for testing which code elements are affected by a
setting. But it's less useful for code samples that are too long to fit the screen. When scrolling to a code region and
applying a change the document is refreshed and the focussed section is lost. 

Expected behaviour: 

The focused section should be preserved as good as possible. the first visible line in the Preview Window could be used
as an anchor point and scrolled to visible after the change.