the same action in two or more projects?
 

is it possible to have the same action in two or more project. It could be useful in some particular cases.

Not at the present. There are some clunky workarounds, probably the easiest is to just duplicate the action in the various projects, along with a note or links to the other ones so you can check them all off when you do any one.

A recent discussion of this is [URL="http://forums.omnigroup.com/showthread.php?t=12782"]here[/URL] and probably the most valuable thing to get from it is to send email to [email]omnifocus@omnigroup.com[/email] (or use Help->Send Feedback) to put in a vote for such a feature if you need it.