Hello Raphael,

I have been investigating into your requirement in this case, and it sounds like you are looking to customize the square that shows up on the day that represents “today.” Currently, this is only customizable using the corresponding MonthViewTodayHighlightBrush and the MonthViewTodayTextBrush. It is not possible to modify the shape of this highlight at the moment.

If you would like to see the ability to customize the month view “today” highlight shape, I would recommend suggesting a new product idea for this at our Xamarin Ideas Site. This will place you in direct communication with our product management teams who plan and prioritize upcoming features and development based on community and user feedback.

Please let me know if you have any other questions or concerns on this matter.