Highlight text with different colors

Proposed from an user: I notice when rephrasing I tend to keep old sentences until I'm fully happy. I love the purple color when using insert because is shows what sentence was used, but the color disappears as soon as you edit it. So maybe an idea to make it possible for people to highlight certain texts with colors? I know it could help me greatly, like coloring old text and attaching a note I have to safekeep it temporarily. I now use strike or italic, but since it's all one color it can get confusing fast.