Can't save changes to 3D Warehouse model

Tried to make some changed to descriptive text, and add a URL.

But after making them, the Save Changes button remains greyed out.

Refreshing the page didn’t help.

??? What to do?

[LATER] Closing the browser and reopening the page did the trick. But what went wrong in the first place? I was logged in, and had just uploaded a revised model.