In section Reports → My sent messages:
If the undelivered message is re-sent, the following window appears:
In fact, when you click the Resend button, the message editor window should not appear, instead the message should be sent again. If there were another button, for example, “edit and re-send”, the meaning of the appearance of the editing window would be. I would like to contact the developers to take into account this moment.
Regards,
Jamshid