More changes to support BollingerBands.

PortfolioManager/ViewModels/MomentumViewModel.cs

@@ -48,6 +48,12 @@ namespace PortfolioManager.ViewModels
       PropertyChanged += OnViewModelPropertyChanged;
     }
 
+    protected override void OnDispose()
+    {
+      MDTrace.WriteLine(LogLevel.DEBUG,$"Dispose MomentumViewModel");
+      base.OnDispose();
+    }        
+
     private void OnViewModelPropertyChanged(object sender, PropertyChangedEventArgs eventArgs)
     {
     }