diff --git a/src/sugar/datastore/datastore.py b/src/sugar/datastore/datastore.py
index b88a8775..1917b19f 100644
--- a/src/sugar/datastore/datastore.py
+++ b/src/sugar/datastore/datastore.py
@@ -278,11 +278,14 @@ def delete(object_id):
     logging.debug('datastore.delete')
     dbus_helpers.delete(object_id)
 
-def find(query, sorting=None, limit=None, offset=None, properties=[],
+def find(query, sorting=None, limit=None, offset=None, properties=None,
          reply_handler=None, error_handler=None):
 
     query = query.copy()
 
+    if properties is None:
+        properties = []
+
     if sorting:
         query['order_by'] = sorting
     if limit:
diff --git a/src/sugar/graphics/palette.py b/src/sugar/graphics/palette.py
index 2c073892..1268726b 100644
--- a/src/sugar/graphics/palette.py
+++ b/src/sugar/graphics/palette.py
@@ -1032,6 +1032,7 @@ class CanvasInvoker(Invoker):
         self._position_hint = self.AT_CURSOR
         self._motion_hid = None
         self._release_hid = None
+        self._item = None
 
         if parent:
             self.attach(parent)
@@ -1093,7 +1094,7 @@ class ToolInvoker(WidgetInvoker):
     def _get_alignments(self):
         parent = self._widget.get_parent()
         if parent is None:
-            return WidgetInvoker.get_alignments()
+            return WidgetInvoker._get_alignments()
 
         if parent.get_orientation() is gtk.ORIENTATION_HORIZONTAL:
             return self.BOTTOM + self.TOP