@Martin280
Martin, are you the only person running this computer?
You have a javascript or a custom box running in Google 'Developer'Console!
Go into Console and you will see this screen......
Do you see any errors when you look at the developer console on that page? Any unfinished work or errors will show up in your system tools.
Do you have any custom code that could be affecting things, or any javascript that might be running? Are there any conditions or actions on your models that might be changing the models (and causing the pop-up)?
If any of these item are open close them and this problem will stop haunting you.
It's only there because you or someone else has not closed off a program, not just a browsing page Martin.
Good luck mate!
Cheers......Rob