[NoMoreNicksLeft]

Why can't code editors have a default-on feature where they show any invisible character (other than newlines)? I seem to remember Sublime doing this at least in some cases... the characters were rendered as a lozenge shape with the hex value of the character.

Is there ever a circumstance where the invisible characters are both legitimate and you as a software developer wouldn't want to see them in the source code?

[ted_dunning]

Check out emacs for options like this.

And, yes, there is a circumstance if you want to include Arabic or Hebrew in comments or strings. You need the zero width left-right markers to make that work.