I have tested all and I know, when systemmessages will be shown and when not.
If I write a message to myself, "sendto"-field is red after send, because it is not possible, send to myself messages. I write a accept username then in this field, send message and now I become message "Message was sent".
If I write a message first to correct user without errormessage before, message was sent but no systemmessage "message was sent" will be shown.
If first JomSocal report cfsr-attack (or so^^) and send then other content of message, systemmessage will be shown also
. Only if I send at first a correct message to correct user I missing systemmessage "Meesage was sent".
Regards Danny