Markup tools in Preview mode

When reading back through files, I would like to be able to have basic markdown functionality such as highlighting and commenting. Although I can already highlight by going into edit mode, when I am reading back for revision purposes, I am normally working in a different window. This feature would therefore allow me to streamline my workflows so that I can focus on the main topic at hand.


Do you mean the ==Highlight text== notation.

Do you mean <!-- comment -->?