[imp] a mail moved to sent-mail but dont sent

[alois blasbichler]

hello list

we have running HORDE 2.2.4 with IMP 3.2.2 on Linux with cyrus and postfix for a
long time - without errors.

Yesterday a user has noticed the following problem (reproducible):

He has written a new E-Mail and copyd a lot of adresses (about 80) from a text
in the To-Header (with cat and paste) and send it.
This E-Mail then was in the sent-mail folder. 
But this E-Mail dont goes away.
In the log-file of the server i dont see nothing from this mail, no error no
notice.

It seems that IMP moved this E-Mail only in the folder "sent-mail" without
sending it. 

Sending a e-mail by copying 10 adresses works fine, is there a limit? 
I dont get an error, so for me it seems a problem of the Mail-Client IMP.

Maybe somebody else have seen a similar problem or can test this?

thank you
luis