How to delete calendar categories and disable others from syncing

before syncing Google mail bug Google-account sync adds existing calendar entries I used to use my work email in my Xperia XA2, after this bug appeared I’ve turned off syncing emails from work email. This added some categories to my phone.
Koli update fixed this, so I turned on syncing, but I have some problems with these categories now:

  1. How can I delete older categories from calendar syncs from Google mail.

    Because when I turned sync on with my work email, all categories shows up again.

  2. When sync is turned on, I see many of categories are selected, but I would like to have some of them.
    When I unselect some of them it still appears in my calendar.
    Has anyone same issues like me?


Still persist in
After each sync, all possible calendars have been marked to syncing, even you disable them few minutes ago.