How to change color of an activity in Calendar Main View?

[Nicolas_Feldman]

Hi everyone,
I´m trying to change the color of the activities in my Main Calendar View.
I´ve tried using Format Rules and it works properly, although the format is only applied to the Details View, and not on the Calendar View. Any ideas on how to achieve this?

The colors on the activities on the posted image , were chosen automatically (red and orange) and cannot find how to change those, and also add an icon if possible.

IN this image, you can see the format rule has been applied correctly to the details view:

Thanks!