couchgrid does not display any column unless keys are set

I should be able to create a couchgrid like this:
        self.__web_hist_grid = CouchGrid("searchy", record_type="web_search")
        self.__web_hist_grid.show()
        self.builder.get_object("viewport_web_hist").add(self.__web_hist_grid)

However, it does not display any columns unless I use a key, like this:
        self.__web_hist_grid = CouchGrid("searchy", record_type="web_search")
        self.__web_hist_grid.keys = ["text"]
        self.__web_hist_grid.show()
        self.builder.get_object("viewport_web_hist").add(self.__web_hist_grid)