The email client Mozilla Thunderbird comes with a few mail filters preinstalled that can be used to automatically process incoming emails. The actions that can be selected as a Thunderbird filter are limited to moving, copying, deleting, forwarding or tagging messages, adding stars, setting mail priorities, marking as read, setting the junk status or replying with templates. While the actions do include several of the most used filters they do lack some actions that are available in other mail clients.
The experimental Mozilla Thunderbird 3 add-on FiltaQuilla adds those additional actions to the Thunderbird Filter settings, in particular filters to launch a software program, append text to subjects, remove tags or stars, mark the email as replied or unread, copy the mail as read or disable notifications.
Probably the most interesting filter of this list is the filter to launch a file after receiving an email message that meets the requirements.

Each Thunderbird filter can be activated and deactivated in the options of the Thunderbird add-on. The mail filters can be selected in the Tools > Message Filters menu.
The Thunderbird add-on is unfortunately only compatible with Thunderbird 3 and not with the more widely used Thunderbird 2. Thunderbird 3 is currently available in Beta 1.
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For me Thunderbird 3 filters are really messing things up.
Every new email which is filtered into a folder is being marked as “READ” before I even see it. Every un-filtered email stays “UNREAD” until read – the way it is supposed to be.
I nearly lost several hundred $$ today when a client’s order went into his folder and was marked “READ”. I have seen several similar postings on the Help forums but no one from Mozilla has responded with an answer.
You guys have anything?