Created attachment 578526 [details] message.html User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:8.0) Gecko/20100101 Firefox/8.0 Build ID: 20111104165243 Steps to reproduce: I'm receiving emails using Thunderbird 8.0. Actual results: Sometimes when I receive answers to emails I sent, I can see only quoted "original message" but I cannot see actual reply that sender wrote. The same message is correctly displayed by Outlook 2003. If I save the message as HTML from Thunderbird and open the file in Firefox 8.0 there is the same issue: I can see only quoted "original message" but I cannot see actual reply that sender wrote. If I open the same file in Internet Explorer version 8 or 9 I can see the full message, like using Outlook. Please find attached "message.html", which is an edited version of the original message and which triggers the issue in Thunderbird / Firefox. This issue is triggered by <!--[if !mso]> tag that Outlook and Outlook Express programs sometimes add when replying to my emails. Please note that this tag is added only sometimes: I can get from the same sender, which uses always the same Outlook version, some emails without this tag and other emails with it. I got this issue from senders which use Outlook (X-Mailer: Microsoft Office Outlook 11, X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6157) and also from senders which use Outlook Express (X-Mailer: Microsoft Outlook Express 6.00.2900.5931, X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6157). All senders are from far east countries like Corea, China and Taiwan. Expected results: Thunderbird should display the full message like Outlook does.
According to the HTML specification <!--[if !mso]>foo<![endif]--> is a single HTML comment (whose value is "[if !mso]>foo<![endif]"). Comment nodes aren't displayed. Thus, Thunderbird is behaving spec-wise correctly for text/html messages. My first reaction was to WONTFIX this, but I realize there might be a need to interop with the Microsoft products that do a bad, bad thing. However, before adding non-standard behaviors to the HTML parser, I'd like to understand how often the problem occurs, whether we can get Microsoft to fix it at their end and whether the outgoing HTML Thunderbird sends can be tweaked so that this behavior isn't triggered in Outlook or Outlook Express when replying.
How do non-Outlook, non-Thunderbird email clients that support text/html message bodies (e.g. Apple's and Opera's email clients, Gmail, etc.) behave when receiving messages like these?
Adding non-standard behavior in a Mozilla product to fix a Microsoft bug really rubs me raw.
And this isn't a regression from the old parser
This bug is just invalid.
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