The autocomplete settings should be moved out into the main UI in the area where they are used. By adding another option at the top of your autocomplete display, users would easily find it.
-- MatthewBarnes 2011-03-09 03:32:14 Making autocomplete settings accessible from the composer window makes sense, but I'm not sure about making it a submenu of an autocomplete list. For one thing, it means you have to autocomplete an email address to even get to the settings. What if instead we add an address book icon to the right side of the entry box. You could click the address book icon and get a popup menu similar to what you show above. The menu should have a short title at the top to clarify what it's for (e.g. Autocomplete from these books). The popup menu should stay up until you click outside of it, so you can click multiple checkboxes without it disappearing on you. Question: should the icon appear in just the To: entry or in all three entries: To:, Cc:, Bcc:? (I think I'd say just To:, but not 100% sure.)