diff --git a/traits_enaml/tests/test_trait_operators.py b/traits_enaml/tests/test_trait_operators.py
index 1ed5783..0dee781 100644
--- a/traits_enaml/tests/test_trait_operators.py
+++ b/traits_enaml/tests/test_trait_operators.py
@@ -13,7 +13,7 @@
 #----------------------------------------------------------------------------
 import unittest
 
-from traits.api import Event, HasTraits, Str
+from traits.api import Event, HasTraits, Str, List, Dict, Set
 from traits_enaml.testing.enaml_test_assistant import EnamlTestAssistant
 
 
@@ -23,6 +23,9 @@ class TraitModel(HasTraits):
     value_update = Str()
     value_simple = Str('simple_text')
     value_notify = Event()
+    list_values = List(Str)
+    dict_values = Dict(Str, Str)
+    set_values = Set(Str)
 
 
 class TraitOperatorsTestCase(EnamlTestAssistant, unittest.TestCase):
@@ -52,6 +55,15 @@ def setUp(self):
         name = 'test_op_notify'
         text ::
             model.value_notify = True
+    Field:
+        name = 'test_list_subscribe'
+        text << str(model.list_values)
+    Field:
+        name = 'test_dict_subscribe'
+        text << str(model.dict_values)
+    Field:
+        name = 'test_set_subscribe'
+        text << str(model.set_values)
 """
         self.model = TraitModel()
         view, toolkit_view = self.parse_and_create(
@@ -74,7 +86,7 @@ def test_op_delegate(self):
 
         self.assertEquals(self.model.value_delegate, 'new_value')
 
-        with self.assertAtomChanges(enaml_widget, 'text'):
+        with self.assertAtomChanges(enaml_widget, 'text', count=1):
             self.model.value_delegate = 'updated_trait'
 
         self.assertEquals(enaml_widget.text, 'updated_trait')
@@ -86,7 +98,7 @@ def test_op_subscribe(self):
         with self.assertTraitDoesNotChange(self.model, 'value_subscribe'):
             enaml_widget.text = 'new_value'
 
-        with self.assertAtomChanges(enaml_widget, 'text'):
+        with self.assertAtomChanges(enaml_widget, 'text', count=1):
             self.model.value_subscribe = 'updated_trait'
 
         self.assertEquals(enaml_widget.text, 'updated_trait')
@@ -127,5 +139,72 @@ def test_op_notify(self):
         with self.assertTraitDoesNotChange(self.model, 'value_notify'):
             enaml_widget.text = 'changing text'
 
-        with self.assertTraitChanges(self.model, 'value_notify'):
+        with self.assertTraitChanges(self.model, 'value_notify', count=1):
             enaml_widget.text = 'new text'
+
+    def test_list_subscribe(self):
+
+        enaml_widget = self.view.find('test_list_subscribe')
+
+        with self.assertTraitDoesNotChange(self.model, 'list_values'):
+            enaml_widget.text = 'new_value'
+
+        # check on replace
+        with self.assertAtomChanges(enaml_widget, 'text', count=1):
+            self.model.list_values = ['1']
+            self.assertEquals(enaml_widget.text, "['1']")
+
+        # check on append
+        with self.assertAtomChanges(enaml_widget, 'text', count=1):
+            self.model.list_values.append('2')
+            self.assertEquals(enaml_widget.text, "['1', '2']")
+
+        # check on remove
+        with self.assertAtomChanges(enaml_widget, 'text', count=1):
+            self.model.list_values.remove('1')
+            self.assertEquals(enaml_widget.text, "['2']")
+
+    def test_dict_subscribe(self):
+
+        enaml_widget = self.view.find('test_dict_subscribe')
+
+        with self.assertTraitDoesNotChange(self.model, 'list_values'):
+            enaml_widget.text = 'new_value'
+
+        # check on replace
+        with self.assertAtomChanges(enaml_widget, 'text', count=1):
+            self.model.dict_values = {'one': '1'}
+            self.assertEquals(enaml_widget.text, "{'one': '1'}")
+
+        # check on append
+        with self.assertAtomChanges(enaml_widget, 'text', count=1):
+            self.model.dict_values['two'] = '2'
+            self.assertEquals(
+                enaml_widget.text, str({'one': '1', 'two': '2'}))
+
+        # check on remove
+        with self.assertAtomChanges(enaml_widget, 'text', count=1):
+            del self.model.dict_values['one']
+            self.assertEquals(enaml_widget.text, "{'two': '2'}")
+
+    def test_set_subscribe(self):
+
+        enaml_widget = self.view.find('test_set_subscribe')
+
+        with self.assertTraitDoesNotChange(self.model, 'list_values'):
+            enaml_widget.text = 'new_value'
+
+        # check on replace
+        with self.assertAtomChanges(enaml_widget, 'text', count=1):
+            self.model.set_values = {'1'}
+            self.assertEquals(enaml_widget.text, "TraitSetObject(['1'])")
+
+        # check on append
+        with self.assertAtomChanges(enaml_widget, 'text', count=1):
+            self.model.set_values.add('2')
+            self.assertEquals(enaml_widget.text, "TraitSetObject(['1', '2'])")
+
+        # check on remove
+        with self.assertAtomChanges(enaml_widget, 'text', count=1):
+            self.model.set_values.remove('1')
+            self.assertEquals(enaml_widget.text, "TraitSetObject(['2'])")
diff --git a/traits_enaml/traits_tracer.py b/traits_enaml/traits_tracer.py
index 4d4627a..f5d5df5 100644
--- a/traits_enaml/traits_tracer.py
+++ b/traits_enaml/traits_tracer.py
@@ -61,6 +61,9 @@ def _trace_trait(self, obj, name):
         trait = obj.trait(name)
         if trait is not None and trait.trait_type is not Disallow:
             self.traced_traits.add((obj, name))
+            # Check for collections.
+            if trait.handler.has_items:
+                self.traced_traits.add((obj, '{}_items'.format(name)))
 
     #--------------------------------------------------------------------------
     # AbstractScopeListener Interface