The Spell Check Setup Page

Selecting Options > Setup General Options then clicking on Spell Check in the left-side navigation panel allows you to delete words from your custom spelling dictionary (this dictionary holds words that were added with the Learn button during spell checking). If you find any misspelled words in the dictionary you'll want to delete them -- otherwise, when you do a spell check the program will pass by any words in your project that have the same misspelling. To delete a word from the custom dictionary, highlight the word to be deleted then click on Delete Highlighted.