Email: Menu for selecting assigned volunteers when sending email (allow choosing of all assigned vs active only).

[dospromptman]

Alternatively, the action to send emails to volunteers might be better off implemented as a list action button rather than an action button on the detail page for the position/activity/shift. This would allow users to choose exactly which volunteers they want to email, but there may be a limit of only selecting up to 200 recipients this way (this should be verified when considering this option). Using a list action button may be preferable to a detail button with custom menu for filtering, since it allows the user full control of the recipient list based on the assigned volunteers.