src/vs/workbench/contrib/notebook/browser/notebookEditorWidget.ts/NotebookEditorWidget/updateShadowElement
class NotebookEditorWidget:	private updateShadowElement(shadowElement: HTMLElement, dimension?: IDimension, position?: DOM.IDomPosition) {
		this._shadowElement = shadowElement;
		if (dimension && position) {
			this._shadowElementViewInfo = {
				height: dimension.height,
				width: dimension.width,
				top: position.top,
				left: position.left,
			};
		} else {
			// We have to recompute position and size ourselves (which is slow)
			const containerRect = shadowElement.getBoundingClientRect();
			this._shadowElementViewInfo = {
				height: containerRect.height,
				width: containerRect.width,
				top: containerRect.top,
				left: containerRect.left
			};
		}
	}