If you want to remove category from categories sidebar widget than go to category option and in the list of name which you want to hide take your cursor on edit link of that name than you will see a number in the address bar shown below, in this screenshot the number is 1 this is the category id for this category cat 1.
- If you do not want to show this category in category widget which shown as
- Than you can write this code which shown in custom css section of epanel which is Theme options in Extra theme
- So you want to hide any category than make a code like above example with respective category id and add to custom css section of epanel.
I hope this will help you a lot.