Attribute missing in object at line 734 of "message_window.pyc"
Traceback (most recent call last): File "message_window.pyc", line 734, in _on_notebook_switch_page AttributeError: 'NoneType' object has no attribute 'set_control_active'
Traceback (most recent call last): File "message_window.pyc", line 734, in _on_notebook_switch_page AttributeError: 'NoneType' object has no attribute 'set_control_active'