I use TextWranger to maintain several simple text files on my mac. The past few updates included a gutter area which is visible by default. Since these are simple text files I did not wish to see it but could not locate a way to disable it within the UI.
I browsed the Google Groups and found a
thread which exposes the setting using defaults. In short:
defaults write com.barebones.textwrangler Editor:Gutter -bool false
Now TextWranger opens with it hidden but I can quickly enable it if needed. I am using version 3.5.3 - hopefully it will be a visible option in future versions.