Thank you for the feedback Per. Yes, the interface is mostly changed cosmetically, not with a lot of new features. But, the entire website was ported to a completely different technology stack, so it was very new under the hood.
Regarding the save and load button, I am not sure why they are not enabled and working correctly if you are logged in with a valid Google account. I need to make sure that it works even if you did not activate your Google+ account. I’ll test it out and fix it if there is a problem there. Please let me know if there is an error message, or any way to reproduce it.
The Save and Load buttons should work by storing your diagram (and settings) on the remote server, so you can load it from another computer. The Refresh button, on the other hand, always stores your diagram in the “local storage” on the one computer you are using at that moment. The next time you go to the website it automatically loads the diagram from the browsers local storage. So this is fine if you are always using the same computer and browser. But, you can use the Save and Load buttons to retrieve your diagram from a different computer or browser.
Thanks again for the feedback!