The widget is ready for that but it would required looking at the content states. Should be easy.
Created attachment 512730 [details] [diff] [review] Patch v1
Comment on attachment 512730 [details] [diff] [review] Patch v1 Looks good, but please request another review from roc because I'm not a peer for the xpwidgets code. One thing: I'm not sure whether you should bother with the content null check since we mostly skip it in the rest of the file. The only cases when I've seen frames with null content was during frame destruction and when the frame is an nsViewportFrame, and none of those cases can be hit in native theme drawing as far as I know.
Created attachment 512748 [details] [diff] [review] Patch v1.1 r=mstange
Created attachment 513140 [details] [diff] [review] Patch v1.2 I realized I should use nsWidgetAtoms intsead of nsGkAtoms.
Backed out in http://hg.mozilla.org/mozilla-central/rev/dd9ba28d2bd9 to resolve bug 655860.
The regression wasn't caused by these patches. Re-landed: http://hg.mozilla.org/mozilla-central/rev/9e265e80c3ff