[imp] compose window resets with large attachments

[Andrew Morgan]

One of my users found a small bug in IMP.  If you try to upload an 
attachment larger than upload_max_filesize, the attachment fails (good) 
but the compose window resets (bad).  Any information you have typed into 
the compose window, such as To: addresses, the Subject, or body text, will 
be lost.

I'm running Horde v3.1.4 and IMP 4.1.4.  upload_max_filesize is set to 
10MB and post_max_size is also set to 10MB.  In imp/config/conf.php I 
have:

$conf['compose']['attach_size_limit'] = '104857600';

(100MB total for all attachments).

I'm guessing that PHP isn't passing the form variables to the script when 
the POST size is exceeded.  If this is the case, would it be possible to 
put a size limit into IMP instead?  Then I could increase the php.ini 
limits to 15MB, but let IMP enforce the 10MB per attachment limit.

Should I file a bug on this?

Thanks,
 	Andy