Fixed DeleteWindow and allowed it to close.

PcgsInvUi/Views/DeleteWindow.axaml.cs

@@ -9,5 +9,6 @@ public partial class DeleteWindow : ReactiveWindow<DeleteWindowViewModel> {
     public DeleteWindow() {
         InitializeComponent();
         this.WhenActivated(d => d(ViewModel!.OkCommand.Subscribe(Close)));
+        this.WhenActivated(d => d(ViewModel!.CancelCommand.Subscribe(Close)));
     }
-}
+}