It's the magic of keeping it simple ;)
In that spirit, I almost exclusively use vim. I slapped together a few lines of C (ok, so much for KISS %) to generate, blank, clone, invert (e.g. '/' to '\') and paste-into the panels...but boy do I suck at coding.
I should've probably just vimproved my macro skills instead.
Anyway, these are my only utilities.