improve default setting for start and end

git-svn-id: svn://svn.cy55.de/Zope3/src/cybertools/trunk@3179 fd906abe-77d9-0310-91a1-e0d9ade77398

organize/work.py

@@ -233,7 +233,11 @@ class WorkItem(Stateful, Track):
             self.reindex('timeStamp')
         data = self.data
         for k, v in kw.items():
+            if v is not None:
                 data[k] = v
+        start, end = data.get('start'), data.get('end')
+        if start and end and end < start:
+            data['end'] = start
 
     def createNew(self, action, userName, copyData=None, **kw):
         if copyData is None: