NullReferenceException-in-Evolver-on-Kalman-indicator

I want to make some adjustments to the Evolver, including deleting some of the default strategy genes. When you click the right mouse button & delete, this error message comes up several times.

Description:

System.NullReferenceException: Object reference not set to an instance of an object.
at finantic.Kalman.Kalman1Price_Estimate.Populate()
at WealthLab.Indicators.IndicatorFactory.ReconcileIndicator(IndicatorBase ib, BarHistory bh, List`1 indicators)
at WealthLab.Indicators.IndicatorFactory.ReconcileDummy(IndicatorBase ib)
at WealthLab.Core.Parameter.GetIndicatorDesc()
at WealthLab.Backtest.IndicatorCrossesSignalLine.get_Description()
at WealthLab8.cwStrategyEvolver.IncludeReponse(Object config, SelectionChangedEventArgs pred)
at System.Windows.Controls.SelectionChangedEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
at System.Windows.Controls.ListBox.OnSelectionChanged(SelectionChangedEventArgs e)
at System.Windows.Controls.Primitives.Selector.InvokeSelectionChanged(List`1 unselectedInfos, List`1 selectedInfos)
at System.Windows.Controls.Primitives.Selector.SelectionChanger.SelectJustThisItem(ItemInfo info, Boolean assumeInItemsCollection)
at System.Windows.Controls.ListBox.MakeSingleSelection(ListBoxItem listItem)
at System.Windows.Controls.ListBox.MakeKeyboardSelection(ListBoxItem item)
at System.Windows.Controls.ListBox.OnGotKeyboardFocus(Object sender, KeyboardFocusChangedEventArgs e)
at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
at System.Windows.Input.InputManager.ProcessStagingArea()
at System.Windows.Input.KeyboardDevice.ChangeFocus(DependencyObject focus, Int32 timestamp)
at System.Windows.Input.KeyboardDevice.Focus(DependencyObject focus, Boolean askOld, Boolean askNew, Boolean forceToNullIfFailed)
at System.Windows.Input.KeyboardDevice.Focus(IInputElement element)
at System.Windows.UIElement.Focus()
at System.Windows.Controls.ItemsControl.FocusItem(ItemInfo info, ItemNavigateArgs itemNavigateArgs)
at System.Windows.Controls.ListBox.FocusItem(ItemInfo info, ItemNavigateArgs itemNavigateArgs)
at System.Windows.Controls.ItemsControl.NavigateByLineInternal(Object startingItem, FocusNavigationDirection direction, FrameworkElement startingElement, ItemNavigateArgs itemNavigateArgs, Boolean shouldFocus, FrameworkElement& container)
at System.Windows.Controls.ItemsControl.NavigateByLine(ItemInfo startingInfo, FrameworkElement startingElement, FocusNavigationDirection direction, ItemNavigateArgs itemNavigateArgs)
at System.Windows.Controls.ItemsControl.NavigateByLine(FocusNavigationDirection direction, ItemNavigateArgs itemNavigateArgs)
at System.Windows.Controls.ListBox.OnKeyDown(KeyEventArgs e)
at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
at System.Windows.Input.InputManager.ProcessStagingArea()
at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
at System.Windows.Interop.HwndKeyboardInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawKeyboardActions actions, Int32 scanCode, Boolean isExtendedKey, Boolean isSystemKey, Int32 virtualKey)
at System.Windows.Interop.HwndKeyboardInputProvider.ProcessKeyAction(MSG& msg, Boolean& handled)
at System.Windows.Interop.HwndSource.CriticalTranslateAccelerator(MSG& msg, ModifierKeys modifiers)
at System.Windows.Interop.HwndSource.OnPreprocessMessage(Object param)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)