Render and draw updated **static** electrode actuations layer on
        canvas.

def on_electrode_states_set(self, states):
        '''
        Render and draw updated **static** electrode actuations layer on
        canvas.
        '''
        if (self.canvas_slave.electrode_states
                .equals(states['electrode_states'])):
            return

        self.canvas_slave.electrode_states = states['electrode_states']

        surface = self.canvas_slave.render_static_electrode_state_shapes()
        self.canvas_slave.set_surface('static_electrode_state_shapes', surface)
        self.canvas_slave.cairo_surface = flatten_surfaces(self.canvas_slave
                                                           .df_surfaces)
        gobject.idle_add(self.canvas_slave.draw)