I am in the process of creating a site, and suddenly am having major problems creating new widgets. It used to work fine, but today, when I drag a new widget (I tried text widgets at first, but I have found it does this with any type of widget) into the sidebar, the Title, Text and other boxes display very briefly and then disappear. All I can do is save or delete the empty box.
I still have full editing control over the existing boxes, but can't create a new one. This happens on all browsers I have tried on MacOS 10.8.5.
Any ideas? Could it be a permissions issue?