It would be great to have the option to enable the following: most of our projects have lots of "read only" users, which are assigned to the project, only to be able to see issues, not participate actively in them. As a consequence, the list of possible assignees ist very long an full of users, who normally aren't chosen.

One idea would be to enhance the dropdown with optgroups, listing participating users first, e.g.:

• participating users ** ** issue creator ** other issue participant
• other users ** user a ** user b ** user c

comments? other suggestions?

thanks for a great software!
Tobias