Bitfields for DESQview mailbox object flags | 
| Bit | Description | 
|---|---|
| 
 0  | 
all mail messages in common memory | 
| 
 1  | 
allow write even if closed | 
| 
 2  | 
don't erase messages when mailbox closed | 
| 
 4  | 
(DV/X) append messages with like status and sender (stream-oriented mail) | 
| 
 5  | 
(DV/X) store mail in expanded memory (pool grows as needed) | 
| 
 6  | 
(DV/X) make mailbox into non-owned mailbox |