--- a/web/facet.py	Wed Feb 17 15:57:03 2010 +0100
+++ b/web/facet.py	Wed Feb 17 15:58:09 2010 +0100
@@ -512,6 +512,9 @@
     def get_widget(self):
         """return the widget instance to use to display this facet"""
         values = set(value for _, value in self.vocabulary() if value is not None)
+        # Rset with entities (the facet is selected) but without values
+        if len(values) == 0:
+            return None
         return self.wdgclass(self, min(values), max(values))
 
     def infvalue(self):