Update

Author: QilongTang

src/DynamoCoreWpf/ViewModels/Core/DynamoViewModel.cs

@@ -11,6 +11,7 @@
 using System.Threading.Tasks;
 using System.Windows;
 using System.Windows.Controls;
+using System.Windows.Forms;
 using System.Windows.Media;
 using System.Windows.Threading;
 using Dynamo.Configuration;