Problem:
Same symbol for 'composing messages' in the 'Preference' menu, the 'Sent' symbol in the 'Mail' menu and the 'send' button when composing a new mail.
solution:
Same symbol makes sense for 'Sent' and 'send' but 'composing messages' should have a different symbol, more like the 'compose' symbol in the navigation column. (consistency and standards)