src/vs/workbench/contrib/debug/browser/callStackView.ts/CallStackDataSource/hasChildren
class CallStackDataSource:	hasChildren(element: IDebugModel | CallStackItem): boolean {
		if (isDebugSession(element)) {
			const threads = element.getAllThreads();
			return (threads.length > 1) || (threads.length === 1 && threads[0].stopped) || !!(this.debugService.getModel().getSessions().find(s => s.parentSession === element));
		}

		return isDebugModel(element) || (element instanceof Thread && element.stopped);
	}