I use the Atom editor with the minimap and minimap-titles packages.
In VisualStudio, they're not nearly as apparent
Alas, I know you can't (probably) do anything about the way MS shows their map mode for the scroll bar.
What I would like is a way to enter titles into the code.
And to have the titles (all block characters) be highlighted differently. I'm not sure they'll ever be legible in the map except for words that are mirror images of themselves :-(
If you don't mind trying a different approach to finding points of interest in your code files, you may well find VA Hashtags helps. It does work differently, but it is designed to list marker points, and let you jump to them:
I use VA Hashtags, Outline and the toolbar and I miss them (esp. Hashtags) when I have to use Atom. I've gotten use to seeing the more physical representation of my file in Atom's minimap. I find Visual Studio's map scrollbar to be lacking (mirrored and too small).
Think you could highlight the VA Hashtags in the map scrollbar (like bookmarks are done)?