Maybe it would also be useful to add two rules actions:

• Open the message

• Open the message's folder

This is a thread for gathering all wishes about the filtering rules.

My main wish is that the choice between 'when folder is opened' and 'when folder is closed' should be postponed in the decision process.

My reason for this is that all people I work with, or 95% of them, including people with scientific doctorate, already have difficulties in creating filtering rules on their own. Therefore I would like them to concentrate on the criteria and the consequent action first. Asking them to chose between Opened and Closed on the first stage, whereas they were making the effort of concentrating on the selection criterion, would kill their motivation.

Maybe in that sense Opened or Closed folder could be a scrolling list at the end of the decision process. In the same way, Opened and Closed folder rules could be presented in the same list, allowing the user to edit them to change this parameter at will. 

I also think that, mostly, it is power users who will use the Closed folder parameter. This imho justifies making the interface simpler for new users, proposing closed folder only at the last stage and only in a scrolling list where Opened folder is default, and not creating another list of rules for Closed folder. Power users will always find their way in such a newbies' adapted interface.

As mentioned in this thread, some filtering rules could also be applied to outgoing mail.

For instance, if I send to so-and-so, apply this identity, or apply this signature, etc...

Today I wanted to add a rule to an address which already has a rule. It is a sender who already has a dedicated folder, and I wanted to add "Play a sound" because I need this person's reply urgently.

Well, I could not add a rule in the window of the previous "Move to folder" rule. It would be so convenient if I had a + button like in Thunderbird.

I find it unelegant and unintuitive to add an item in the rules list, for exactly the same sender.