1. Select the underline option
2. Underline text by selecting
3. Right click on underlined text and change it to a highlight color
4. Underline text again by selecting
5. Right click again on underlined text and choose a different color
The new highlighted color will be a mix of the two different
Sort of like mixing food coloring, for example try mixing two yellows with a pink.

 ![Screenshot][1]


  [1]: https://i.sstatic.net/1j9aB.png