diff --git a/gramps/gui/configure.py b/gramps/gui/configure.py
index 1bd231c1b..08baf06c7 100644
--- a/gramps/gui/configure.py
+++ b/gramps/gui/configure.py
@@ -220,6 +220,27 @@ class ConfigureDialog(ManagedWindow):
         except:
             print("WARNING: ignoring invalid value for '%s'" % constant)
 
+    def update_markup_entry(self, obj, constant):
+        """
+        :param obj: an object with get_text method 
+        :param constant: the config setting to which the text value must be 
+            saved
+        """
+        try:
+            obj.get_text() % 'test_markup'
+        except TypeError:
+            print("WARNING: ignoring invalid value for '%s'" % constant)
+            ErrorDialog(_("Invalid or incomplete format definition."), 
+            obj.get_text())
+            obj.set_text('<b>%s</b>')
+        except ValueError:
+            print("WARNING: ignoring invalid value for '%s'" % constant)
+            ErrorDialog(_("Invalid or incomplete format definition."),
+            obj.get_text())
+            obj.set_text('<b>%s</b>')
+        
+        self.__config.set(constant, unicode(obj.get_text()))
+
     def update_entry(self, obj, constant):
         """
         :param obj: an object with get_text method 
@@ -1167,7 +1188,7 @@ class GrampsPreferences(ConfigureDialog):
                 6, 'behavior.avg-generation-gap', (10, 30))
         self.add_pos_int_entry(table,
                 _('Markup for invalid date format'), 
-                7, 'preferences.invalid-date-format', self.update_entry)
+                7, 'preferences.invalid-date-format', self.update_markup_entry)
 
         return _('Dates'), table