In particular, this can be observed by comparing the rendering of fast/forms/basic-selects.html and fast/forms/basic-textareas-quirks.html with the pixel dump from the Mac port.
This should be working for select controls now, but is still an issue for input type=text.
Created attachment 71959 [details] Patch for this issue
Created attachment 74795 [details] Patch without changes to text area scrollbars as well
I think Xan preferred that I remove the change to the scrollbar rendering. I'll open a new bug for that. The new patch also doesn't have updated pixel results, but I'll generate them before landing the patch.
Comment on attachment 74795 [details] Patch without changes to text area scrollbars as well r=me
Committed r73128: <http://trac.webkit.org/changeset/73128>
Committed r76748: <http://trac.webkit.org/changeset/76748>