src/vs/workbench/contrib/notebook/browser/view/cellParts/foldedCellHint.ts/FoldedCellHint/update
class FoldedCellHint:	private update(element: MarkupCellViewModel) {
		if (!this._notebookEditor.hasModel()) {
			return;
		}

		if (element.isInputCollapsed || element.getEditState() === CellEditState.Editing) {
			DOM.hide(this._container);
		} else if (element.foldingState === CellFoldingState.Collapsed) {
			const idx = this._notebookEditor._getViewModel().getCellIndex(element);
			const length = this._notebookEditor._getViewModel().getFoldedLength(idx);
			DOM.reset(this._container, this.getHiddenCellsLabel(length), this.getHiddenCellHintButton(element));
			DOM.show(this._container);

			const foldHintTop = element.layoutInfo.previewHeight;
			this._container.style.top = `${foldHintTop}px`;
		} else if (element.foldingState === CellFoldingState.Expanded) {
			DOM.hide(this._container);
		}
	}