diff --git a/src/message/__init__.py b/src/message/__init__.py
index 268922c..0709be3 100644
--- a/src/message/__init__.py
+++ b/src/message/__init__.py
@@ -1,7 +1,7 @@
 from message.simple_messages import NoReset, Reset, ModalNotOkClose, ClickMessage, DataChgClickMessage, KeyboardPress
 from message.translation_edit import EditTranslation, MoveRight, MoveLeft, BinTranslation
 from message.show_messages import ShowEntryLabelsEdit, ShowEditTranslation, ShowSenseLabelEdit, ShowSenseDefinitionEdit, ShowCommentEdit, ShowAddTranslation, ShowExampleEdit, ShowVariantsEdit, ShowRelatedEntriesEdit
-from message.simple_edits import EditSenseLabel, EditSenseDefinition, EditComment, AddSenseLabel, AddSense, AddExampleTranslation, DoChosenExamples, AddToLabelList, AddToGenericList, EditVariants, EditRelatedEntries, EditEntryLabels
+from message.simple_edits import EditSenseLabel, EditSenseDefinition, EditComment, AddSenseLabel, AddSense, AddExampleTranslation, DoChosenExamples, AddToLabelList, AddToGenericList, EditVariants, EditRelatedEntries, EditEntryLabels, ExampleClusterEdit
 from message.show_menu import ShowTranslationMenu, ShowSenseMenu, ShowExampleMenu
 from message.sense_edit import SenseMoveUp, SenseMoveDown, SenseBin
 from message.example_edit import ExampleMoveUp, ExampleMoveDown, ExampleBin, ExampleRoleChange, ExampleComponentAdd, ExampleComponentRemove, EditExampleText, ToggleExamples
diff --git a/src/message/simple_edits.py b/src/message/simple_edits.py
index 0cb2a54..f3ce15e 100644
--- a/src/message/simple_edits.py
+++ b/src/message/simple_edits.py
@@ -100,4 +100,9 @@ class EditEntryLabels(Message):
         model.entry.labels = labels
         
         
+class ExampleClusterEdit(Message):
+    def update_model(self, model):
+        example = self.get_arg(0, Example)
+        cluster = self.get_arg(1, int)
+        example.set_cluster(cluster)
         
diff --git a/src/model/sense.py b/src/model/sense.py
index 6e0ec75..6c45824 100644
--- a/src/model/sense.py
+++ b/src/model/sense.py
@@ -27,19 +27,20 @@ class Sense(Editable):
                          sense_xml.querySelectorAll("exampleContainerList exampleContainer")]
         
         # set limit for example cluster
-        self.reserved_example = max(cluster_mappings.values()) + 1
-        cluster_min = self.reserved_example + 1
+        cluster_min =max(cluster_mappings.values()) + 2
+        
+        self._original_examples = set([cluster_min - 1])
+        self._original_examples = set(self.example_clusters())
     
     def merge_labels(self):
         return ", ".join(val for _, val in self.labels)
     
     def example_clusters(self):
-        result = set()
+        result = self._original_examples
         for ex in self.examples:
             cluster = ex.get_cluster()
             if cluster is not None:
                 result.add(cluster)
-        result.add(self.reserved_example)
         
         return sorted(result)
                 
diff --git a/src/view/utils.py b/src/view/utils.py
index e2651eb..00bcee0 100644
--- a/src/view/utils.py
+++ b/src/view/utils.py
@@ -1,18 +1,25 @@
 from export import export_to_xml
 from browser import window
 from lib.snabbdom import h
+import message
 
 
 NUM2STR = "123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
 
 def show_toggle_cluster_buttons(sense, example):
+    cls = example.get_cluster()
+    if cls is None:
+        return []
+    
     result = []
     for opt in sense.example_clusters():
         tag = "input.cluster-list-button"
-        if opt == example.get_cluster():
+        if opt == cls:
             tag += ".cluster-button-checked"
             
-        result.append(h(tag, {"attrs": {"value": NUM2STR[opt], "type": "button"}}, []))
+        result.append(h(tag, 
+                        {"attrs": {"value": NUM2STR[opt], "type": "button"},
+                         "on": {"click": message.msg(message.ExampleClusterEdit(example, opt))}}, []))
     return result