Shared components used by Firefox and other Mozilla software, including handling of Web content; Gecko, HTML, CSS, layout, DOM, scripts, images, networking, etc. Issues with web page layout probably go here, while Firefox user interface issues belong in the Firefox product. (More info)
Created attachment 299597[details]
Gecko-2008012704 and Nautilus, Ubuntu-7.04
GTK disables the the arrow button on top of the scroll-bar when the handler cannot be more up.
Please look at the [^] arrow on nautilus's scrollbar and the one on fx3.0.