@@ -1770,20 +1770,33 @@ class DotWidget(gtk.DrawingArea):

         return (time.time() < self.presstime + click_timeout

                 and math.hypot(deltax, deltay) < click_fuzz)

+    def on_click(self, element, event):

+        """Override this method in subclass to process

+        click events. Note that element can be None

+        (click on empty space)."""

+        return False

+

     def on_area_button_release(self, area, event):

         self.drag_action.on_button_release(event)

         self.drag_action = NullAction(self)

-        if event.button == 1 and self.is_click(event):

-            x, y = int(event.x), int(event.y)

-            url = self.get_url(x, y)

-            if url is not None:

-                self.emit('clicked', unicode(url.url), event)

-            else:

-                jump = self.get_jump(x, y)

-                if jump is not None:

-                    self.animate_to(jump.x, jump.y)

+        x, y = int(event.x), int(event.y)

+        if self.is_click(event):

+            el = self.get_element(x, y)

+            print "clicked element:", el

+            if self.on_click(el, event):

+                return True

+

+            if event.button == 1:

+                url = self.get_url(x, y)

+                if url is not None:

+                    self.emit('clicked', unicode(url.url), event)

+                else:

+                    jump = self.get_jump(x, y)

+                    if jump is not None:

+                        self.animate_to(jump.x, jump.y)

+

+                return True

-            return True

         if event.button == 1 or event.button == 2:

             return True

         return False

@@ -1863,7 +1876,7 @@ class DotWindow(gtk.Window):

     base_title = 'Dot Viewer'

-    def __init__(self):

+    def __init__(self, widget=None):

         gtk.Window.__init__(self)

         self.graph = Graph()

@@ -1875,7 +1888,7 @@ class DotWindow(gtk.Window):

         vbox = gtk.VBox()

         window.add(vbox)

-        self.widget = DotWidget()

+        self.widget = widget or DotWidget()

         # Create a UIManager instance

         uimanager = self.uimanager = gtk.UIManager()