The Source Editor has a word match feature. Type the first few letters of a word. Then press Ctrl-K or Ctrl-L. If there is another word in the file that begins with the same letters, the word is completed for you automatically.

If you press Ctrl-K, the IDE searches backward through the file and completes the word according to the first match it finds. If you press Ctrl-L, the IDE searches forward to find a match.