diff --git a/tests/test_js_instanceproperties.py b/tests/test_js_instanceproperties.py
index 19d17e546..64b093aef 100644
--- a/tests/test_js_instanceproperties.py
+++ b/tests/test_js_instanceproperties.py
@@ -136,3 +136,18 @@ def test_on_event_handleEvent_fail(self):
         """)
         self.assert_failed(with_errors=True)
 
+    def test_on_event_handleEvent_ignore(self):
+        """
+        Test that dirty objects don't trigger handleEvent errors.
+        """
+
+        self.setup_err(for_appversions=FX18_DEFINITION)
+
+        self.run_script("""
+        var dirty = this_creates_a_dirty_object();
+        foo.onclick = dirty;
+        """)
+        self.assert_silent()
+
+
+
diff --git a/validator/testcases/javascript/instanceproperties.py b/validator/testcases/javascript/instanceproperties.py
index c5ece3d74..a2f46c9b8 100644
--- a/validator/testcases/javascript/instanceproperties.py
+++ b/validator/testcases/javascript/instanceproperties.py
@@ -104,7 +104,8 @@ def set_on_event(new_value, traverser):
             line=traverser.line,
             column=traverser.position,
             context=traverser.context)
-    elif not is_literal and new_value.has_property("handleEvent"):
+    elif (not is_literal and isinstance(new_value.value, jstypes.JSObject) and
+          "handleEvent" in new_value.value.data):
         mess_type = (traverser.err.error if
                      traverser.err.supports_version(FX18_DEFINITION) else
                      traverser.err.warning)