Hi Mits, thanks for your reply!
Actually I checked the aspects thru "manage aspects", and don't find any imap related aspects added. Even I removed all the aspects, the properties still exist. I also checked the share-configure/form/model xml-files, and don't find any related revisions. I will keep working it out.
B.T.W.
For the aspect - associations, I know we can use it to build the relationship between documents,
however for the aspect - replaceable, I don't know what we can do with it, and what scenario it could be applied to. Would you please help on this as well? Thanks!