TabControl usage issues

[ZhuoWang-NXNX]

Bug explanation

at MaterialDesignThemes.Wpf.Behaviors.Internal.TabControlHeaderScrollBehavior.OnTabChanged(Object sender, SelectionChangedEventArgs 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.Controls.TabControl.OnSelectionChanged(SelectionChangedEventArgs e)
at System.Windows.Controls.Primitives.Selector.SelectionChanger.SelectJustThisItem(ItemInfo info, Boolean assumeInItemsCollection)
at System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
at System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args)
at System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType)
at System.Windows.DependencyObject.SetValueCommon(DependencyProperty dp, Object value, PropertyMetadata metadata, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType, Boolean isInternal)
at System.Windows.DependencyObject.SetCurrentValueInternal(DependencyProperty dp, Object value)
at System.Windows.Controls.TabControl.OnGeneratorStatusChanged(Object sender, EventArgs e)
at System.Windows.Controls.ItemContainerGenerator.SetStatus(GeneratorStatus value)
at System.Windows.Controls.ItemContainerGenerator.Generator.System.IDisposable.Dispose()
at System.Windows.Controls.Panel.GenerateChildren()
at System.Windows.Controls.Panel.get_InternalChildren()
at System.Windows.Controls.Primitives.UniformGrid.UpdateComputedValues()
at System.Windows.Controls.Primitives.UniformGrid.MeasureOverride(Size constraint)
at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
at System.Windows.UIElement.Measure(Size availableSize)
at System.Windows.Controls.StackPanel.StackMeasureHelper(IStackMeasure measureElement, IStackMeasureScrollData scrollData, Size constraint)
at System.Windows.Controls.StackPanel.MeasureOverride(Size constraint)
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.ScrollContentPresenter.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.MeasureOverride(Size constraint)
at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
at System.Windows.UIElement.Measure(Size availableSize)
at System.Windows.Controls.ScrollViewer.MeasureOverride(Size constraint)
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.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.Grid.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.Controls.DockPanel.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 MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, 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.Control.MeasureOverride(Size constraint)
at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
at System.Windows.UIElement.Measure(Size availableSize)
at System.Windows.Controls.Grid.MeasureOverride(Size constraint)
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.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.Control.MeasureOverride(Size constraint)
at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
at System.Windows.UIElement.Measure(Size availableSize)
at System.Windows.ContextLayoutManager.UpdateLayout()
at Microsoft.VisualStudio.DesignTools.WpfTap.WpfVisualTreeService.VisualTree.DispatcherVisualTreeContext.UpdateLayout()
at Microsoft.VisualStudio.XSurface.Wpf.DesignerTapInstanceManager.AfterProcessActions(TapInstanceBuilderContext context)

Version

5.3.0

[nicolaihenriksen]

@ZhuoWang-NXNX Can you reproduce this consistently? If so, please indicate which type of exception is thrown as this can give some hints as to what is happening.

[ZhuoWang-NXNX]

Object reference not set to an instance of an object. In the design mode, sometimes it can display normally, and sometimes it throws this error.The operation is normal. However, when an error occurs in the design mode, previewing is not possible. The TabView becomes completely blank and displays a red "x".

…

________________________________ 发件人: Nicolai Henriksen ***@***.***> 发送时间: 2026年6月8日 16:45 收件人: MaterialDesignInXAML/MaterialDesignInXamlToolkit ***@***.***> 抄送: ZhuoWang ***@***.***>; Mention ***@***.***> 主题: Re: [MaterialDesignInXAML/MaterialDesignInXamlToolkit] TabControl usage issues (Issue #4067) [https://avatars.githubusercontent.com/u/19572699?s=20&v=4]nicolaihenriksen left a comment (MaterialDesignInXAML/MaterialDesignInXamlToolkit#4067)<#4067 (comment)> @ZhuoWang-NXNX<https://github.com/ZhuoWang-NXNX> Can you reproduce this consistently? If so, please indicate which type of exception is thrown as this can give some hints as to what is happening. ― Reply to this email directly, view it on GitHub<#4067?email_source=notifications&email_token=BKO7HYRPB5GWBWDDVVFJOH346Z4JTA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTINRUGY4DQNJZHE32M4TFMFZW63VHNVSW45DJN5XKKZLWMVXHJLDGN5XXIZLSL5RWY2LDNM#issuecomment-4646885997>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/BKO7HYWIXD2DNSWHTKMLVGT46Z4JTAVCNFSM6AAAAACZ6LWHSWVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DMNBWHA4DKOJZG4>. Triage notifications, keep track of coding agent tasks and review pull requests on the go with GitHub Mobile for iOS<https://github.com/notifications/mobile/ios/BKO7HYQXAFVBV6MKICPOLND46Z4JTA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTINRUGY4DQNJZHE32M4TFMFZW63VHNVSW45DJN5XKKZLWMVXHJKTGN5XXIZLSL5UW64Y> and Android<https://github.com/notifications/mobile/android/BKO7HYQDBPBPG2QVOQSOQI346Z4JTA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTINRUGY4DQNJZHE32M4TFMFZW63VHNVSW45DJN5XKKZLWMVXHJLTGN5XXIZLSL5QW4ZDSN5UWI>. Download it today! You are receiving this because you were mentioned.Message ID: ***@***.***>

[nicolaihenriksen]

@ZhuoWang-NXNX The designer issue was addressed in #4026 and thus should not occur if you update to version 5.3.2