[horde] DIMP & mail_hdr preference

[Adam Tauno Williams]

Quoting Michael M Slusarz <slusarz at horde.org>
> Quoting Adam Tauno Williams <awilliam at whitemice.org>:
>> Does DIMP not support the mail_hdr preference in preview?
>> I'm setting this via imp/config/prefs.local.php to a value and  
>> setting it to locked.  The headers appear in traditional view but  
>> this does not make the header appear in the DIMP preview [it does  
>> appear if I 'open' the message].
>> Is this not supported or is there a way to toggle-on showing extra  
>> headers in preview?
> Not supported.  Preview is intended to be a simplified view of a message.

Yea, I just figured that out from looking at the source code.

Given that there is a dimp_previewview and dimp_messageview hooks -  
those are probably better places to try to add my customization.   
Basically if the message has a particular header I need to render that  
as a link in the 'header section' of the message display.  On previous  
versions I've just hacked this into the IMP header display.   Is  
something like this possible with hooks?  Are there any examples of  
dimp_ hooks?