def METHOD_NAME(self, event):
    plot = self.component
    data_x, data_y = plot.map_data((event.x, event.y))
    plot.index._data[self._drag_index] = data_x
    plot.value._data[self._drag_index] = data_y
    plot.index.data_changed = True
    plot.value.data_changed = True
    plot.request_redraw()