src/vs/workbench/contrib/notebook/browser/viewModel/markupCellViewModel.ts/MarkupCellViewModel/layoutChange
class MarkupCellViewModel:	layoutChange(state: MarkdownCellLayoutChangeEvent) {
		// recompute
		if (!this.metadata.inputCollapsed) {
			const editorWidth = state.outerWidth !== undefined
				? this.viewContext.notebookOptions.computeMarkdownCellEditorWidth(state.outerWidth)
				: this._layoutInfo.editorWidth;
			const totalHeight = state.totalHeight === undefined ? this._layoutInfo.totalHeight : state.totalHeight;
			const previewHeight = this._previewHeight;

			this._layoutInfo = {
				fontInfo: state.font || this._layoutInfo.fontInfo,
				editorWidth,
				previewHeight,
				editorHeight: this._editorHeight,
				bottomToolbarOffset: this.viewContext.notebookOptions.computeBottomToolbarOffset(totalHeight, this.viewType),
				totalHeight
			};
		} else {
			const editorWidth = state.outerWidth !== undefined
				? this.viewContext.notebookOptions.computeMarkdownCellEditorWidth(state.outerWidth)
				: this._layoutInfo.editorWidth;
			const totalHeight = this.viewContext.notebookOptions.computeCollapsedMarkdownCellHeight(this.viewType);

			state.totalHeight = totalHeight;

			this._layoutInfo = {
				fontInfo: state.font || this._layoutInfo.fontInfo,
				editorWidth,
				editorHeight: this._editorHeight,
				previewHeight: this._previewHeight,
				bottomToolbarOffset: this.viewContext.notebookOptions.computeBottomToolbarOffset(totalHeight, this.viewType),
				totalHeight
			};
		}

		this._onDidChangeLayout.fire(state);
	}