Null reference exception thrown while collapsing ribbon menu with Minimize button Completed

And please find the call stack details here,

at System.Windows.Media.VisualCollection.DisconnectChild(Int32 index)

at System.Windows.Media.VisualCollection.InternalRemove(Visual visual)

at System.Windows.Controls.UIElementCollection.RemoveNoVerify(UIElement element)

at System.Windows.Controls.ItemsControl.MS.Internal.Controls.IGeneratorHost.GetContainerForItem(Object item)

at System.Windows.Controls.ItemContainerGenerator.Generator.GenerateNext(Boolean stopAtRealized, Boolean& isNewlyRealized)

at System.Windows.Controls.ItemContainerGenerator.System.Windows.Controls.Primitives.IItemContainerGenerator.GenerateNext()

at System.Windows.Controls.Panel.GenerateChildren()

at System.Windows.Controls.Panel.EnsureGenerator()

at System.Windows.Controls.Panel.get_InternalChildren()

at Syncfusion.Windows.Tools.Controls.TabPanel.get_VisibleChildren() in D:\Sources\Tools.WPF\tools-wpf\WPF\Tools.WPF\Src\Framework\Ribbon\Implementation\TabPanel.cs:line 164

at Syncfusion.Windows.Tools.Controls.TabPanel.MeasureOverride(Size availableSize) in D:\Sources\Tools.WPF\tools-wpf\WPF\Tools.WPF\Src\Framework\Ribbon\Implementation\TabPanel.cs:line 828

at System.Windows.FrameworkElement.MeasureCore(Size availableSize)

at System.Windows.UIElement.Measure(Size availableSize)

at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint)

at System.Windows.Controls.ItemsPresenter.MeasureOverride(Size constraint)

at System.Windows.FrameworkElement.MeasureCore(Size availableSize)

at System.Windows.UIElement.Measure(Size availableSize)

at System.Windows.Controls.Border.MeasureOverride(Size constraint)

at System.Windows.FrameworkElement.MeasureCore(Size availableSize)

at System.Windows.UIElement.Measure(Size availableSize)

at System.Windows.Controls.DockPanel.MeasureOverride(Size constraint)

at System.Windows.FrameworkElement.MeasureCore(Size availableSize)

at System.Windows.UIElement.Measure(Size availableSize)

at System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV)

at System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV, Boolean& hasDesiredSizeUChanged)

at System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV)

at System.Windows.Controls.Grid.MeasureOverride(Size constraint)

at System.Windows.FrameworkElement.MeasureCore(Size availableSize)

at System.Windows.UIElement.Measure(Size availableSize)

at System.Windows.Controls.Border.MeasureOverride(Size constraint)

at System.Windows.FrameworkElement.MeasureCore(Size availableSize)

at System.Windows.UIElement.Measure(Size availableSize)

at System.Windows.Documents.AdornerDecorator.MeasureOverride(Size constraint)

at System.Windows.FrameworkElement.MeasureCore(Size availableSize)

at System.Windows.UIElement.Measure(Size availableSize)

at System.Windows.Controls.Control.MeasureOverride(Size constraint)

at System.Windows.FrameworkElement.MeasureCore(Size availableSize)

at System.Windows.UIElement.Measure(Size availableSize)

at System.Windows.ContextLayoutManager.UpdateLayout()

at System.Windows.ContextLayoutManager.UpdateLayoutCallback(Object arg)

at System.Windows.Media.MediaContext.InvokeOnRenderCallback.DoWork()

at System.Windows.Media.MediaContext.FireInvokeOnRenderCallbacks()

at System.Windows.Media.MediaContext.RenderMessageHandlerCore(Object resizedCompositionTarget)

at System.Windows.Media.MediaContext.RenderMessageHandler(Object resizedCompositionTarget)

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)

at System.Windows.Threading.DispatcherOperation.InvokeImpl()

at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state)

at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)

at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)

at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)

at MS.Internal.CulturePreservingExecutionContext.Run(CulturePreservingExecutionContext executionContext, ContextCallback callback, Object state)

at System.Windows.Threading.DispatcherOperation.Invoke()

at System.Windows.Threading.Dispatcher.ProcessQueue()

at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)

at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)

at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)

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)

at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)

at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)

at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)

at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)

at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)

at System.Windows.Application.RunDispatcher(Object ignore)

at System.Windows.Application.RunInternal(Window window)

at System.Windows.Application.Run(Window window)

at System.Windows.Application.Run()

at WpfAppTestSyncfusion.App.Main()