Hi Vivian,

it depends what you mean exactly by "highlight'. Are you referring to the selected days? Or do you mean the ActiveDay? Or do you mean some arbitrary dates you want to highlight because they are significant, like holidays or events?

These doesn't appear to be any properties to affect the color of the day outside of the header. But you can achieve this using a DrawFilter. I am attaching a small sample project demonstrating this technique on the selected days.

Let me know if you have any questions.