'Map Mode' scroll bar is an enhanced scroll bar introduced by Microsoft from Visual Studio 2013. This enables users to see a preview of their code as you scrolling the scroll bar.
If you don't have VS 2013, don't worry. Even I am working with a VS 2012 instance and luckily Microsoft has provided an extension of tools that has this scroll bar. You can download 'Productivity Power Tools' using this link and use the Map Mode scroll bar.
In VS 2013, you can enable this by going to Options->Text Editor->All Languages -> Scroll Bars-> choosing 'Use Map Mode for verticals scroll bars' under behavior section to make it available for all the languages.
This will gives you to hoover over any part of the code in the scroll bar to directly see the code. Also it will mark any errors using a red dot in the scroll bar itself. So it is easy to find if you make any silly mistakes on the go.
If you don't have VS 2013, don't worry. Even I am working with a VS 2012 instance and luckily Microsoft has provided an extension of tools that has this scroll bar. You can download 'Productivity Power Tools' using this link and use the Map Mode scroll bar.
In VS 2013, you can enable this by going to Options->Text Editor->All Languages -> Scroll Bars-> choosing 'Use Map Mode for verticals scroll bars' under behavior section to make it available for all the languages.
This will gives you to hoover over any part of the code in the scroll bar to directly see the code. Also it will mark any errors using a red dot in the scroll bar itself. So it is easy to find if you make any silly mistakes on the go.
I just started using this, will see how it goes.