“Re: I Want an Outliner for Code Writing”

Vim has a feature called folding which fits your request precisely... except that maybe you'd have to do a key combination instead of double-clicking the left part of the line. But I don't know, maybe you'd be able to pull that off too.

Granted, this suggestion is only valid if you enjoy working in a vi-like environment. I didn't like it at first but I have come to be incredibly productive in it...

-Brian