When you edit your gmail settings, recently you often get this message if you move the focus away from the settings pane:
Your changes have not been saved.
Discard changes?
The odd thing is that the settings are indeed saved just before you move the focus away.
So I always wondered if the message can be really ignored, and this thread confirms the message indeed is harmless.
I do still wonder why I get this message mostly in FireFox and Internet Explorer, but almost never in Chrome 
–jeroen
