I was wondering how hard, if it isn't impossible, would it be to include #if 0 ... #endif as a comment with syntax colouring as well as adding bold/highlight coloured for FIXME, TODO, XXX if found in a comment.
More simple : use an external editor.
Delta_G:
To make a word show up colored, just add it to a keywords.txt file in one library. You could even have a dummy library with no code and just the keywords file.
That still doesn't highlight words that are found inside comments however.
heh, thus this suggestion for future a future Arduino IDE feature