Another standard feature missing in Opera is support for forwarding a message as an attachment.
With Outlook Express, Thunderbird and Sylpheed for example, you get an explicit "Forward as attachment" option that composes a new message with the original message attached as a message/rfc822 attachment (the data of the attachment is basically the original source of the message).
Then, if you get a message like this, you can choose to open the attachment as a separate message.
Opera doesn't support this and you have to do the following to work around it:
- Open the message and ctrl + s to save the message as file.mbs
- Rename file.mbs to file.eml.
- Open file.eml in a text editor and remove the "From " line (the first line) to make it look like the eml format.
- Goto "Ctrl + F12 -> advanced -> downloads", edit the message/rfc822 type and add ",eml" to its extension list.
- Ctrl + m to compose new message and type the original subject prefixed by "Fwd: ".
- Attach file.eml to the message.
Now, in Opera, you can attach mbs files to a message and they'll be sent with an application/mime type where supporting clients will recognize the attachments as messages. And, if Opera sees a message like this, it'll shows the original messages embedded with a border (but no way to open it separately). But, this doesn't work in as many clients as the message/rfc822 way. Either way, being able to explicitly "forward as attachment" (even for text-only messages) is nice.