Source Mail
Result Handling
Now that you have a joined list of all possible identities, you have to decide what has to be done with the results. All possible identities will be added to the identity dropdown menu.
In most cases, especially if you configured the filters for Smart identity detection right, the topmost identity is the one you are interested in. Therefore it's an good idea to select the first found identity without further queries [default on].
Beside, it might be appropriate to use any other identity from the list, if this matches any of your permanent identities - this option is [on by default]. See for yourself if this fit's your requirements.
If there is more than one identity (or even if there is only one resulting identity), you can choose to get an dialog to select the identity you like to use. These options are [off by default] but might make your life easier if you usually don't like to use any virtual identity at all.