When initializing a CanvasSpace on a container that already contains a canvas, the size attribute of the CanvasSpace instance does not get updated with the canvas element's size, resulting in empty renderings. This case should be supported according to documentation ("an id property which refers to the "id" attribute of the canvas element in DOM. If no canvas element with this id is found, a new canvas element will be created."). I'd also see dropping this use case from the docs as a quicker solution.