public Task CollapseAllNodes(ISolutionManager solutionManager) { if (solutionManager == null) { throw new ArgumentNullException(nameof(solutionManager)); } return(NuGetUIThreadHelper.JoinableTaskFactory.Run(async delegate { await NuGetUIThreadHelper.JoinableTaskFactory.SwitchToMainThreadAsync(); await VsHierarchyUtility.CollapseAllNodesAsync(solutionManager, _expandedNodes); return Task.CompletedTask; })); }