Class: ucp_pm  - X-Ref

Private Message Class

$_REQUEST['folder'] display folder with the id used
$_REQUEST['folder'] inbox|outbox|sentbox display folder with the associated name

Display Messages (default to inbox) - mode=view
Display single message - mode=view&p=[msg_id] or &p=[msg_id] (short linkage)

if the folder id with (&f=[folder_id]) is used when displaying messages, one query will be saved. If it is not used, phpBB needs to grab
the folder id first in order to display the input boxes and folder names and such things. ;) phpBB always checks this against the database to make
sure the user is able to view the message.

Composing Messages (mode=compose):
To specific user (u=[user_id])
To specific group (g=[group_id])
Quoting a post (action=quotepost&p=[post_id])
Quoting a PM (action=quote&p=[msg_id])
Forwarding a PM (action=forward&p=[msg_id])