The gutter's width has size of its last visible line number. So when you scroll a file with lots of lines, gutter gets expanded more and more (as the amount of digits in line number increases).
It a perfect word, it should be of the same size all the time.
Created attachment 191744 [details]
Comment on attachment 191744 [details]
You should not change third party files in place. This diverges things and results in merging conflicts.
Created attachment 191956 [details]
Comment on attachment 191956 [details]
Clearing flags on attachment: 191956
Committed r145064: <http://trac.webkit.org/changeset/145064>
All reviewed patches have been landed. Closing bug.