Index: editors/js/fckeditor-2.6.js
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/wysiwyg/editors/js/fckeditor-2.6.js,v
retrieving revision 1.16.2.2
diff -u -p -r1.16.2.2 fckeditor-2.6.js
--- editors/js/fckeditor-2.6.js	6 Feb 2010 15:27:41 -0000	1.16.2.2
+++ editors/js/fckeditor-2.6.js	10 Feb 2010 22:24:43 -0000
@@ -87,7 +87,9 @@ Drupal.wysiwyg.editor.instance.fckeditor
           data = Drupal.wysiwyg.plugins[plugin].detach(data, Drupal.settings.wysiwyg.plugins.drupal[plugin], instance.FCK.Name);
         }
       }
-      return data;
+      // Remove unwanted <p> or <br /> tags left when nothing was entered,
+      // to allow truly empty fields. This seems to be fixed for CKEditor.
+      return data.replace(/^(?:<p>(?:&nbsp;|\s*)<\/p>|<br(?:\s\/)?>)$/i, '');
     };
     instance.FCK.DataProcessor = new wysiwygDataProcessor();
   },