any way to turn off vertical Diff bar in left hand gutter?

This is pretty minor, but it has been bugging me. In the gutter, where line numbers display, etc, a vertical colored bar is displayed whenever I make changes (e.g. insert new lines).  This is distracting to me, and I'm not sure why it's there, as the stripe marks indicating Diffs are already displayed (unobtrusively) on the right-hand side.

Any way to disable the Diff bar on the left-hand side?

Thanks.