Not opening up 4D Mail messages

[nobody]

I use 4D Mail which is both a POP and IMAP server.  When I try to open 
any messages it appears that Roundcube is downloading the message, 
but then nothing displays.  It doesn't even open up another message 
window in attempt to display it.  I've asked this question before but 
have not had any responses over the past couple of weeks.  When I 
asked the question of my Webstar mailing list members if they have 
tried Roundcube out to see if they were having the same issues.  One 
response was: 

"The problem is 4Dmail implementation of IMAP. Roundcube would 
need to  be aware of 4dmail mailbox format. Talk to the developers."

I do not know if this is the problem or not.  I do know that Squirrelmail 
does not have this issue and there are several Webstar administrators 
that would love to use Roundcube, myself included.  How can we get 
Roundcube to function correctly with 4D Mail?

I tried running Roundcube with Apache and had the exact same 
problems... but it was still pulling mail from the same 4D Mailserver.  
The clues are pointing to a compatibility issue with 4D Mail.  If you can 
get this to work with 4D Mail, you'll be a hero!

If it helps, you can go to their website, 4d.com and download their 
webmail program.  They have a lite and full version, but perhaps you 
can use it to determine where the problem is.  If there is any other 
information you may need from me, please let me know.

[thomasb]

Related to #1375919. The problem is that 4D Mail does not support SEARCH commands.