Exception when TextBox in PopupBox is bound to FocusManager.FocusedElement

Description

When you put a TextBox in a PopupBox and bind the text box to FocusManager.FocusedElement you will get an InvalidOperationException

Exception Message

'ScaleTransform' name cannot be found in the name scope of 'System.Windows.Controls.ControlTemplate'.

Stack Trace

   at System.Windows.Media.Animation.Storyboard.ResolveTargetName(String targetName, INameScope nameScope, DependencyObject element)
   at System.Windows.Media.Animation.Storyboard.ClockTreeWalkRecursive(Clock currentClock, DependencyObject containingObject, INameScope nameScope, DependencyObject parentObject, String parentObjectName, PropertyPath parentPropertyPath, HandoffBehavior handoffBehavior, HybridDictionary clockMappings, Int64 layer)
   at System.Windows.Media.Animation.Storyboard.ClockTreeWalkRecursive(Clock currentClock, DependencyObject containingObject, INameScope nameScope, DependencyObject parentObject, String parentObjectName, PropertyPath parentPropertyPath, HandoffBehavior handoffBehavior, HybridDictionary clockMappings, Int64 layer)
   at System.Windows.Media.Animation.Storyboard.BeginCommon(DependencyObject containingObject, INameScope nameScope, HandoffBehavior handoffBehavior, Boolean isControllable, Int64 layer)
   at System.Windows.Media.Animation.BeginStoryboard.Begin(DependencyObject targetObject, INameScope nameScope, Int64 layer)
   at System.Windows.StyleHelper.InvokeEventTriggerActions(FrameworkElement fe, FrameworkContentElement fce, Style ownerStyle, FrameworkTemplate frameworkTemplate, Int32 childIndex, RoutedEvent Event)
   at System.Windows.StyleHelper.ExecuteEventTriggerActionsOnContainer(Object sender, RoutedEventArgs e)
   at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   at System.Windows.FrameworkElement.OnGotFocus(RoutedEventArgs e)
   at System.Windows.UIElement.IsFocused_Changed(DependencyObject d, DependencyPropertyChangedEventArgs e)
   at System.Windows.DependencyObject.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
   at System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
   at System.Windows.Controls.TextBox.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.SetValue(DependencyPropertyKey key, Object value)
   at System.Windows.Input.FocusManager.OnFocusedElementChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
   at System.Windows.DependencyObject.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
   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.InvalidateProperty(DependencyProperty dp, Boolean preserveCurrentValue)
   at System.Windows.Data.BindingExpressionBase.Invalidate(Boolean isASubPropertyChange)
   at System.Windows.Data.BindingExpression.TransferValue(Object newValue, Boolean isASubPropertyChange)
   at System.Windows.Data.BindingExpression.Activate(Object item)
   at System.Windows.Data.BindingExpression.AttachToContext(AttachAttempt attempt)
   at System.Windows.Data.BindingExpression.MS.Internal.Data.IDataBindEngineClient.AttachToContext(Boolean lastChance)
   at MS.Internal.Data.DataBindEngine.Task.Run(Boolean lastChance)
   at MS.Internal.Data.DataBindEngine.Run(Object arg)
   at System.Windows.ContextLayoutManager.fireLayoutUpdateEvent()
   at System.Windows.ContextLayoutManager.UpdateLayout()
   at System.Windows.ContextLayoutManager.UpdateLayoutCallback(Object arg)
   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)

Expected Behaviour

No exception and text box is focused when popup is opened.

Pseudo XAML

<PopupBox>
    <Grid FocusManager.FocusedElement="{Binding ElementName=MyTextBox}">
        <TextBox Name="MyTextBox"/>
    </Grid>    
</PopupBox>

Analysis

The pseudo XAML worked fine on version 2.4 but fails on version 2.5.

This issue seems related to the commit https://github.com/MaterialDesignInXAML/MaterialDesignInXamlToolkit/commit/8010f856bc9f116e4ee01584566dc004837e190e because it introduces a new ScaleTransform:

https://github.com/MaterialDesignInXAML/MaterialDesignInXamlToolkit/blob/cf4f48b0193329aef8078e3aed38b21352f3b982/MaterialDesignThemes.Wpf/Themes/MaterialDesignTheme.TextBox.xaml#L64

The scale transform is animated by GotFocus and LostFocus event triggers: https://github.com/MaterialDesignInXAML/MaterialDesignInXamlToolkit/blob/cf4f48b0193329aef8078e3aed38b21352f3b982/MaterialDesignThemes.Wpf/Themes/MaterialDesignTheme.TextBox.xaml#L245-L270

Perhaps @spiegelp can investigate this issue?

Reproduction Link

No repo for this issue yet.

[BryceBarbara]

Nevermind, it definitely was fixed in 2.5.1. Since I ensured I had the most recent stable version in NuGet, I figured I was using that version. Turns out 2.5.1 is prerelease so I needed to check for that before I saw the right version.

[mgnslndh]

Ok thanks for looking into this! I’ll have to see if I can reproduce it in isolation.