Mozilla Connect

In Mac versioni of Thunderbird cannot open automatically .Pages attachments, but always see them as txt/dms files and propose TextEdit as only one opening option.

I can ask thunderbird to cancel messages in Junk folder after a number of day I want to on my IMAP accounts. Why it is not possible for the Trash folder? I don't what to cancel them immediately, but I wait to have a option that cancel them after some...