private void treeSetsDoubleClick(object sender, MouseButtonEventArgs args) { if (!DoubleEvent) { DoubleEvent = true; if (_ActiveDeck == null) { MessageBox.Show("Please select a deck first."); return; } if (_ActiveDeck != null && ActiveCard != null) { _ActiveDeck.RegisterCard(ActiveCard); try { NotifyPropertyChanged("ObservableDecks"); } catch (InvalidOperationException e) { treeviewDecks.SetValue(TreeView.SelectedItemProperty, null); treeviewSets.SetValue(TreeView.SelectedItemProperty, null); //NotifyPropertyChanged("ObservableDecks"); } } } else { DoubleEvent = false; } }