src/vs/workbench/contrib/notebook/browser/notebookEditorWidget.ts/NotebookEditorWidget/updateContextKeysOnFocusChange
class NotebookEditorWidget:	private updateContextKeysOnFocusChange() {
		if (!this.viewModel) {
			return;
		}

		const focused = this._list.getFocusedElements()[0];
		if (focused) {
			if (!this._cellContextKeyManager) {
				this._cellContextKeyManager = this._localStore.add(this.instantiationService.createInstance(CellContextKeyManager, this, focused as CellViewModel));
			}

			this._cellContextKeyManager.updateForElement(focused as CellViewModel);
		}
	}