I suppose it's nothing too new google's checking out there, it kind of reminds me of the FCKeditor (which probably does not look into the stuff you write)...

trace-uk: This problem can be solved using a JavaScript as one of my freemail providers does - set a cookie with the text you've typed every once in a while; delete it on hitting the save-button; check for it when the editing page is loaded; if it exists, ask whether the previous text shall be restored...