User-defined dictionary in Arbortext

I created a user-defined dictionary with userdict command from the command prompt. The dictionary file is located at the default location  lib/proximity/userdict, I was under the assumption that the words in the dictionary file would not display the red wavy underline when spelling check is used on an opened document in Arbortext.  However, the words on the document which were also on the dictionary file are still display with red wavy underline. If someone can provide the reasons why and the solutions to make the user-defined dictionary to work as intended, your inputs are greatly appreciated.