http://lxr.mozilla.org/seamonkey/source/layout/html/style/src/nsCSSFrameConstructor.cpp#5105
http://lxr.mozilla.org/seamonkey/source/layout/xul/base/src/nsNativeScrollbarFrame.cpp#91
http://lxr.mozilla.org/seamonkey/source/layout/xul/base/src/nsSliderFrame.cpp#253