Hidden QRT settings

Users also have the ability to set whether the QRT visibility is retained, or not, each time the return workbook is opened.
To set this option you should login as Administrator -> go to System Admin in the Tabular ribbon and select Settings.
There in the System Options tab, you can see Hidden QRT settings section.

By default Auto-unhide QRTs option in not selected. So when you or someone else will open again return workboook, all hidden earlier QRTs will still be hidden.

But if you will select Auto-unhide QRTs option, on the next return workbook open all hidden QRTs will be visible again.