Hi,
when attempting to deserialize a saved layout from XML, I get the following exception:

System.InvalidOperationException: 'Collection was modified; enumeration operation may not execute.'

It seems to be reproducable by moving or removing a LayoutAnchrablePane that is contained within the serialized layout and then deserializing the layout.

Here is the deserialization code:

var serializer = new XmlLayoutSerializer(dockingManager); serializer.LayoutSerializationCallback += SerializerLayoutSerializationCallback; [...] using (var stream = new StreamReader(defaultLayout)) { serializer.Deserialize(stream); }

(The exception is thrown somewhere inside serializer.Deserialize(stream);)

StackTrace:

at System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource)
at System.Collections.Generic.List1.Enumerator.MoveNextRare() at System.Collections.Generic.List1.Enumerator.MoveNext()
at Xceed.Wpf.AvalonDock.Layout.Extensions.d__0.MoveNext() in F:\MyFiles\CSharp\00_GitHub\Avalondock\source\Components\Xceed.Wpf.AvalonDock\Layout\Extentions.cs:line 32
at Xceed.Wpf.AvalonDock.Layout.Extensions.d__0.MoveNext() in F:\MyFiles\CSharp\00_GitHub\Avalondock\source\Components\Xceed.Wpf.AvalonDock\Layout\Extentions.cs:line 35
at Xceed.Wpf.AvalonDock.Layout.Extensions.d__0.MoveNext() in F:\MyFiles\CSharp\00_GitHub\Avalondock\source\Components\Xceed.Wpf.AvalonDock\Layout\Extentions.cs:line 35
at Xceed.Wpf.AvalonDock.Layout.Extensions.d__0.MoveNext() in F:\MyFiles\CSharp\00_GitHub\Avalondock\source\Components\Xceed.Wpf.AvalonDock\Layout\Extentions.cs:line 35
at Xceed.Wpf.AvalonDock.Layout.Extensions.d__0.MoveNext() in F:\MyFiles\CSharp\00_GitHub\Avalondock\source\Components\Xceed.Wpf.AvalonDock\Layout\Extentions.cs:line 35
at Xceed.Wpf.AvalonDock.Layout.Extensions.d__0.MoveNext() in F:\MyFiles\CSharp\00_GitHub\Avalondock\source\Components\Xceed.Wpf.AvalonDock\Layout\Extentions.cs:line 35
at System.Linq.Enumerable.d__951.MoveNext() at Xceed.Wpf.AvalonDock.DockingManager.Layout_ElementAdded(Object sender, LayoutElementEventArgs e) in F:\MyFiles\CSharp\00_GitHub\Avalondock\source\Components\Xceed.Wpf.AvalonDock\DockingManager.cs:line 2976 at Xceed.Wpf.AvalonDock.Layout.LayoutRoot.OnLayoutElementAdded(LayoutElement element) in F:\MyFiles\CSharp\00_GitHub\Avalondock\source\Components\Xceed.Wpf.AvalonDock\Layout\LayoutRoot.cs:line 763 at Xceed.Wpf.AvalonDock.Layout.LayoutElement.OnRootChanged(ILayoutRoot oldRoot, ILayoutRoot newRoot) in F:\MyFiles\CSharp\00_GitHub\Avalondock\source\Components\Xceed.Wpf.AvalonDock\Layout\LayoutElement.cs:line 136 at Xceed.Wpf.AvalonDock.Layout.LayoutElement.set_Parent(ILayoutContainer value) in F:\MyFiles\CSharp\00_GitHub\Avalondock\source\Components\Xceed.Wpf.AvalonDock\Layout\LayoutElement.cs:line 68 at Xceed.Wpf.AvalonDock.Layout.LayoutAnchorable.UpdateParentVisibility() in F:\MyFiles\CSharp\00_GitHub\Avalondock\source\Components\Xceed.Wpf.AvalonDock\Layout\LayoutAnchorable.cs:line 769 at Xceed.Wpf.AvalonDock.Layout.LayoutAnchorable.OnParentChanged(ILayoutContainer oldValue, ILayoutContainer newValue) in F:\MyFiles\CSharp\00_GitHub\Avalondock\source\Components\Xceed.Wpf.AvalonDock\Layout\LayoutAnchorable.cs:line 270 at Xceed.Wpf.AvalonDock.Layout.LayoutElement.set_Parent(ILayoutContainer value) in F:\MyFiles\CSharp\00_GitHub\Avalondock\source\Components\Xceed.Wpf.AvalonDock\Layout\LayoutElement.cs:line 64 at Xceed.Wpf.AvalonDock.Layout.LayoutGroup1._children_CollectionChanged(Object sender, NotifyCollectionChangedEventArgs e) in F:\MyFiles\CSharp\00_GitHub\Avalondock\source\Components\Xceed.Wpf.AvalonDock\Layout\LayoutGroup.cs:line 253
at System.Collections.Specialized.NotifyCollectionChangedEventHandler.Invoke(Object sender, NotifyCollectionChangedEventArgs e)
at System.Collections.ObjectModel.ObservableCollection1.OnCollectionChanged(NotifyCollectionChangedEventArgs e) at System.Collections.ObjectModel.ObservableCollection1.RemoveItem(Int32 index)
at System.Collections.ObjectModel.Collection1.Remove(T item) at Xceed.Wpf.AvalonDock.Layout.LayoutGroup1.RemoveChild(ILayoutElement element) in F:\MyFiles\CSharp\00_GitHub\Avalondock\source\Components\Xceed.Wpf.AvalonDock\Layout\LayoutGroup.cs:line 137
at Xceed.Wpf.AvalonDock.DockingManager.DetachAnchorablesSource(LayoutRoot layout, IEnumerable anchorablesSource) in F:\MyFiles\CSharp\00_GitHub\Avalondock\source\Components\Xceed.Wpf.AvalonDock\DockingManager.cs:line 2917
at Xceed.Wpf.AvalonDock.DockingManager.OnLayoutChanged(LayoutRoot oldLayout, LayoutRoot newLayout) in F:\MyFiles\CSharp\00_GitHub\Avalondock\source\Components\Xceed.Wpf.AvalonDock\DockingManager.cs:line 147
at Xceed.Wpf.AvalonDock.DockingManager.OnLayoutChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) in F:\MyFiles\CSharp\00_GitHub\Avalondock\source\Components\Xceed.Wpf.AvalonDock\DockingManager.cs:line 127
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.SetValueCommon(DependencyProperty dp, Object value, PropertyMetadata metadata, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType, Boolean isInternal)
at System.Windows.DependencyObject.SetValue(DependencyProperty dp, Object value)
at Xceed.Wpf.AvalonDock.Layout.Serialization.XmlLayoutSerializer.Deserialize(TextReader reader) in F:\MyFiles\CSharp\00_GitHub\Avalondock\source\Components\Xceed.Wpf.AvalonDock\Layout\Serialization\XmlLayoutSerializer.cs:line 82
at Alpine.Gui.TestSuite.TestSuiteWindow.LoadDefaultLayout(Object sender, RoutedEventArgs e) in D:#ATAT3\Alpine.Atat\src\Core\Alpine.Gui\TestSuite\TestSuiteWindow.xaml.cs:line 389
at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
at System.Windows.UIElement.RaiseEvent(RoutedEventArgs e)
at System.Windows.Controls.MenuItem.InvokeClickAfterRender(Object arg)
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)

I added the layout I am trying to deserialize:
layout.zip

Kind Regards,
David