There are times when I want to flag a bunch of rows without providing links to each of them. Of course I can color rows, and apply filters. But it would be super cool if the flagged rows were marked on the scroll bar so that you could see them and easily scroll to each of them.
Similar to chrome view source when you do Find on some text. Probably there are more important things, but it would be super cool as our data is context specific so you need the big picture when looking for something.
It's an interesting idea, and quite possible.
Of course some platforms don't display scrollbars, so that adds some interest.
You could add in a docked element which on non-scrollbar platforms is
opacity:0 by default and which turns opaque during scroll (or when the mouse moves over its area). It would always be present docked over the top of the scrollbar for other platforms.
It would contain positioned highlighter elements of proportional height and at the correct top %age
Quite easy, but we have many priorities for many customers.