We noticed an issue when posting articles where the message box is disappeared after a security update. We are investigating the problem and working hard to resolve the problem, please be patient. We will update this post and we will notify users with a ticket as soon as the problem is resolved.
The problem is caused by a conflict in the visual editor, there has been reported lots of issues caused by the update. We implemented a temporary workaround by disabling the visual text editor until there will be a bug-fix available.
If you experience this problem you can make a new ticket and we will pick it up as soon as possible.