src/vs/workbench/contrib/notebook/browser/contrib/outline/notebookOutline.ts/NotebookCellOutline/_recomputeActive
class NotebookCellOutline:	private _recomputeActive(): void {
		let newActive: OutlineEntry | undefined;
		const notebookEditorWidget = this._editor.getControl();

		if (notebookEditorWidget) {
			if (notebookEditorWidget.hasModel() && notebookEditorWidget.getLength() > 0) {
				const cell = notebookEditorWidget.cellAt(notebookEditorWidget.getFocus().start);
				if (cell) {
					for (const entry of this._entries) {
						newActive = entry.find(cell, []);
						if (newActive) {
							break;
						}
					}
				}
			}
		}
		if (newActive !== this._activeEntry) {
			this._activeEntry = newActive;
			this._onDidChange.fire({ affectOnlyActiveElement: true });
		}
	}