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)
I do not see overlapping table cells on the test page. Angus, please
retest and if the problem is still there, provide more information.
Related bugs have been submitted for missing form elements and incorrect style
on this page.