Currently ScrollbarThemeGtk does not support secondary steppers, yet some popular themes (like older versions of Elementary) have these. This bug tracks adding this feature.
Created attachment 65760 [details] Adding alternate stepper support
Comment on attachment 65760 [details] Adding alternate stepper support Looks good to me!
Comment on attachment 65760 [details] Adding alternate stepper support Clearing flags on attachment: 65760 Committed r66845: <http://trac.webkit.org/changeset/66845>
All reviewed patches have been landed. Closing bug.