To
Sort using the To address.
From
Sort using the From address.
Reply To
Sort using the Reply To address.
Sender
Sort using the Sender address.
CC
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Subject
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Thread
Sort using a hierarchic thread display.
Date Sent
Sort using the date sent.
Date Received
Sort using the date received.
Size
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Flags
Sort using the flags.
Number
Sort using the message number.
Smart Address
Sort using the To or From address depending on whether you sent the message.
Attachments
Sort using the type of attachments.
Parts
Sort using the number of attachments.
Matching
Sort using the matched state of the messages.
Disconnected
Sort using the disconnected state of the messages.