InRibbonGallery broken when ItemsSource is empty

[dominiks]

When the ItemsSource for a InRibbonGallery is an empty collection, the popup closes on click to expand the gallery and prints this stacktrace:

System.Windows.Data Error: 8 : Cannot save value from target back to source. BindingExpression:Path=IsDropDownOpen; DataItem='InRibbonGallery' (Name=''); target element is 'ToggleButton' (Name='PART_ExpandButton'); target property is 'IsChecked' (type 'Nullable`1') ArgumentOutOfRangeException:'System.ArgumentOutOfRangeException: Der Parameterwert muss größer Null sein.
Parametername: pixelWidth
   bei System.Windows.Media.Imaging.RenderTargetBitmap..ctor(Int32 pixelWidth, Int32 pixelHeight, Double dpiX, Double dpiY, PixelFormat pixelFormat)
   bei Fluent.InRibbonGallery.set_IsSnapped(Boolean value) in C:\projects\fluent-ribbon\Fluent.Ribbon\Controls\InRibbonGallery.cs:Zeile 723.
   bei Fluent.InRibbonGallery.OnDropDownOpened(Object sender, EventArgs e) in C:\projects\fluent-ribbon\Fluent.Ribbon\Controls\InRibbonGallery.cs:Zeile 1207.
   bei System.Windows.FrameworkElement.RaiseClrEvent(EventPrivateKey key, EventArgs args)
   bei System.Windows.Controls.Primitives.Popup.CreateWindow(Boolean asyncCall)
   bei System.Windows.Controls.Primitives.Popup.OnIsOpenChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
   bei System.Windows.DependencyObject.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
   bei System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
   bei System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args)
   bei System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType)
   bei System.Windows.DependencyObject.InvalidateProperty(DependencyProperty dp, Boolean preserveCurrentValue)
   bei System.Windows.StyleHelper.InvalidateDependents(Style ownerStyle, FrameworkTemplate frameworkTemplate, DependencyObject container, DependencyProperty dp, FrugalStructList`1& dependents, Boolean invalidateOnlyContainer)
   bei System.Windows.StyleHelper.OnTriggerSourcePropertyInvalidated(Style ownerStyle, FrameworkTemplate frameworkTemplate, DependencyObject container, DependencyProperty dp, DependencyPropertyChangedEventArgs changedArgs, Boolean invalidateOnlyContainer, FrugalStructList`1& triggerSourceRecordFromChildIndex, FrugalMap& propertyTriggersWithActions, Int32 sourceChildIndex)
   bei System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
   bei System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args)
   bei System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType)
   bei System.Windows.DependencyObject.SetValueCommon(DependencyProperty dp, Object value, PropertyMetadata metadata, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType, Boolean isInternal)
   bei MS.Internal.Data.PropertyPathWorker.SetValue(Object item, Object value)
   bei System.Windows.Data.BindingExpression.UpdateSource(Object value)'

If the mouse button is held the popup stays open and the gallery's menu items can be used. To reproduce the issue, change the DataItems in the sample to be empty.

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Environment

• Fluent.Ribbon 5.0.2.46
• Windows 10
• .NET Framework 4.5.2

[dominiks]

Thank you for the quick solution.