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)
+++ This bug was initially created as a clone of Bug #777672 +++
Scroll bar of body is always present and overflow content can be scrolled to.
Bug #777672 fixed the UI Tests app case, but make the System app (with lock screen) scrollable :-/