TIdMailBox = class(TIdBaseComponent);

TIdMailBox is a TIdBaseComponent descendant that represents information about a mailbox selected using the IMAP4 protocol. TIdMailBox identifies the Attributes of the mailbox, updateable flags, state information, and the list of messages in the currently seleted mailbox. 

TIdMailBox can also indicate dynamic information, such as message numbers found that meet some search criteria, or a list messages that have been marked for deletion in the mailbox. 

TIdMailBox is the type used to represent the TIdIMAP4.MailBox property, and is updated when the IMAP4 client performs a Select, Examine, or Status operation using the IMAP4 protocol.