Users can't see that an email has been sent to participants

When the meeting is under status "in preparation" you can access to a text-area in order to send an email to participant.
The usability issue is that when you click on "send", it's only refreshing the page in emptying the textarea field. It's not a valid information for the user so he tries again and again until he understand that he just sent 10 emails.

We need to give more visual feedback.
I propose to :

• remember the text written and to fill the textarea with it.
• remember the date when the email has been sent
• Add a text right under/upper the textarea with the date of the last mail sent using the label "Last mail sent on the DATE"