This form is available if the data type is Keywords, Dynamic Keywords or Number List so that you can specify the values that are allowed to be input to the custom field. Allowed values are listed and you can:
•prevent a value being used by clicking 
against it.
•add an allowed value by entering it to the next available Value field, selecting a Display Color and clicking Add
•change the sequence of the list by selecting Manually Order Values and then clicking 
or 
to change an entry’s position. Choosing Sort Values in Alphabetical Order will list the entries in alphabetical order or ascending numerical order. The actual sequence has no system significance.