Event Categories that are currently in use on an Event Calendar can not be deleted.  

To make these eligible for deletion:
  1. Navigate to the page containing the Event Calendar Part where the Category is currently in use and edit the page
  2. Click on the gear icon next to the Event Calendar part and select Edit
  3. Enter the Event Categories section and locate the Category that needs to be deleted 
  4. Click the X next to the category to remove it from the Calendar
    • Note: If the "X" does not appear next to the Category within the Event Calendar Part, this means that there is currently an event on the Calendar that is using this Category.  
      Any Category that is currently in use, can not be deleted.  The event must be deleted first.
  5. Click Save
  6. Navigate to Administration > Code Tables to return to the Event Code Table
  7. Mark the checkbox next to the Event
  8. Click Delete Code Table Entry