I often get a "do you want to leave this site" browser dialog when closing the OMV admin tab. This happens when there is no unsaved information.
2. Click on "scheduled jobs"
3. Close the browser tab
This generates the popup, but it's not necessary.
I can't exactly figure out how the system is determining whether to show this message or not (for example, if you simply log in and then close the tab, no warning is shown). If you login and go to "users" and then close the tab, the message is shown. If you login and go to "disks" it is not.
I'd rather the warning is only shown when I've made a change that hasn't been saved.
I'm on OMV 5.6.0-1, and I've seen the same behaviour on Brave, Chrome, Firefox and Safari (MacOS).