diff --git a/whiteboard/plugin.py b/whiteboard/plugin.py
index 77d23cd..c603835 100644
--- a/whiteboard/plugin.py
+++ b/whiteboard/plugin.py
@@ -69,6 +69,7 @@ class WhiteboardPlugin(GajimPlugin):
                 self.disconnect_from_chat_control),
             'chat_control_base_update_toolbar': (self.update_button_state,
                 None),
+            'update_caps': (self._update_caps, None),
         }
         self.controls = []
         self.sid = None