When Mozilla encounters an XML document which is not well-formed, instead of showing nothing at all, it should show the XML source in the same viewport as the rendered XML was to appear. This would avoid the problem of the XML content not being available when it was actually (unbeknownst to Mozilla) of critical importance. It would also be useful as a debugging tool.

It would also be rather cool to have the line in error highlighted. The XML error message would of course still appear at the top of all this, as required by the XML spec. Nisheeth: If you want to discuss this (post rtm of course) then I would be happy to do so. I think an optimal implementation would be one using elements from its own namespace, a la: <parsererror> <error> error message </error> <!-- whatever is required here --> <source> ... <errorsection title="error message">...</errorsection> ... </source> </parsererror> Then I could do fancy stuff to it in ua.css. ;-)

47416 is related, if not directly blocked, by this suggestion.

Reverted the dependencies. Bug 47416 is much simpler than this one. It is asking for the filename (absolute URL). Once the filename is in the error-struct, there would be enough information in the struct that could be used to produce the custom viewsource (like LXR @ filename#lineNumber) that this more complex bug is asking for.

This bug is still marked as "NEW" since 2000. I don't know how things were back then, but as of FF 1.5x, if you have a WF error, you can always use view-source to see the original (broken) XML. Personally I think this is quite enough and that maybe this bug could be closed?

No, that was also the behavior when I reported this bug, so it's not what this bug is about. I can use View Source, but I shouldn't have to, when there's a perfectly good viewport sitting there nearly empty.

*** Bug 362179 has been marked as a duplicate of this bug. ***

I agree with Matthew Paul Thomas and add that I think that fixing this is important to encourage adoption of the proper MIME type for XHTML. See my description in dupe bug 362179.