Work around to a bug where MAO 'Undo Move' with Gmail IMAP causes mail to disappear

We have received a number of reports from people unable to undo Act-On moves when working with Gmail IMAP. On further investigation this issue seems to be a bug specific to the interaction of Apple Mail and Gmail.

The observed behavior of Mail with no plug-in attached

• Drag and drop a message from gmail to another mailbox and immediately hit undo. Instead of undo it deletes the message from Gmail and the other mailbox.
• Delete a message (backspace) from Gmail and immediately hit undo. The message will flash back and then disappear (into the ether)

In fact, if we move, or delete a message from Gmail and wait about second, the undo menu item is disabled preventing us from undoing. (We believe this is Mail.app, realizing that it is dealing with gmail and trying to compensate for non-standard IMAP behavior.)

The work around

Go to the Gmail labs settings, and enable the advanced IMAP Controls.

Then go the POP/IMAP tab in settings, and click on 'Do not automatically expunge messages'.

That should do the trick. Thanks go out to Paul who stumbled on the fix.