[Evolution] tried to Delete default categories; making changes to Properties of Categories Permanent

[Jeff Co <hanzjordan gmail com>]

I've deleted the default categories (e.g Favorites, Holiday, VIP) but
they keep coming back. How can I get rid of them for good?

I've tried to apply a color to some categories, such as Calls, but
they don't have any color in my task list. When I check the properties
of this Category, I see that the changes I've made (e.g. Color 
changed to Green) is not set. What's wrong