[dev] IMAP delete flag

[Chuck Hagenbuch]

Quoting Michael M Slusarz <slusarz at horde.org>:

>> Hi Jan, that seems to do exactly what I want. I've had a few cases
>> where some emails were still displayed "marked as deleted" in my inbox
>> for a short period, and then vanished when I played with the mailbox
>> sorting... not sure if it's a bug, a caching issue or what.
>
> Don't use caching.  Caching can't pick up flag changes.

In case it's not clear, caching can't pick up flag changes _made in  
other clients_. Flag changes made through Horde of course are reflected.

-chuck