See the attachment
Created attachment 227198 [details]
OK, now I have an answer to my queston of bug 124838 comment 98... The paint call is necessary to draw the background.
Created attachment 227652 [details]
Comment on attachment 227652 [details]
Clearing flags on attachment: 227652
Committed r166170: <http://trac.webkit.org/changeset/166170>
All reviewed patches have been landed. Closing bug.