Message headers / metadata

Problem Once an email is sent, there is no way to cancel or retrieve it, even immediately after sending. Request Add an undo-send window or email recall capability to cancel a sent email within a configurable time period.

Request Always display the CC field when composing emails, rather than requiring additional steps to reveal it.

Problem There's no way to add custom headers to messages sent via a custom SMTP server. Request Support adding custom headers to emails sent through custom SMTP configuration.

Request Expose all email headers, which may contain important information like links in custom header values.

Problem Changing the channel (from address) requires mouse navigation, which is inconvenient for frequent changes. Request Keyboard shortcut to quickly change the channel (from address) when composing messages.