[Support System] No alert on required reply when reopening a ticket (by user)

I have found that when a client reopens a closed ticket - by removing the checkmark next to the status "Close ticket", clicks the Update button and leaves the screen - the status in "My support tickets" becomes "New".

However the ticket has not been reopened and when the client refreshes the page "My support tickets" the status of the ticket is "closed" again. The status never changes in the backend.
Please see this video of the issue: https://www.screencast.com/t/dDTxkbgsMD

This is very confusing to the client. Is there a way to implement an alert that explains that the client also has to enter a reply and click the "submit" button?