Your sign-in to the Formitor dashboard lasts for a limited time. While the dashboard is open and awake it renews itself in the background, so you will not normally notice. A sign-in usually lapses because the tab sat in the background for a long stretch, or the computer went to sleep, and the renewal never had a chance to run.
When you come back to the tab, the dashboard checks the session before you click anything. If it can renew quietly, it does, and you will see nothing. If the session has genuinely ended, an amber banner appears above the sign-in card and tells you so.
Signing back in from that banner returns you to the same place. Nothing you had open is discarded: the page was only hidden while you signed in, so an editor or dialog you had part-way through is still there afterwards. You do not need to reload the page.
If you press Sign out yourself, that is treated as a normal sign-out and you will not see the expiry banner.