Открытое ContextMenu -> RightClick запускает LeftClickCommand в ViewModel

У меня есть ContextMenu, связанный с HierarchicalDataTemplate, который отображает структуру TreeView. ContextMenu также является HierarchicalDataTemplate, который получает свою структуру через ObservableCollection моделей MenuItemViewModels.

Моя проблема в том, что при запуске программы щелчок правой кнопкой мыши по уже открытому ContextMenu нежелательно вызывает щелчок левой кнопкой мыши по элементу MenuItem - почему это так? Что мне не хватает? Я не могу найти ошибку в коде и буду признателен за любую помощь.

XAML для TreeView:

<HierarchicalDataTemplate x:Key = "TreeHierarchicalDataTemplate" DataType = "{x:Type model:TreeNodeBaseViewModel}" ItemsSource = "{Binding Path=SubItems, UpdateSourceTrigger=PropertyChanged}" ItemContainerStyle = "{StaticResource  MenuItemTemplateItemContainerStyle}">
<!--...-->
</HierarchicalDataTemplate>

<Style x:Key = "MenuItemTemplateItemContainerStyle" TargetType = "{x:Type TreeViewItem}">
    <Setter Property = "ContextMenu" Value = "{DynamicResource MenuItemContextMenu}"/>
    <Setter Property = "IsEnabled" Value = "{Binding IsEnabled}"/>
    <Setter Property = "AllowDrop" Value = "{Binding IsDropAllowed}"/>
    <Setter Property = "IsExpanded" Value = "{Binding IsExpanded, Mode=TwoWay}"/>
    <Setter Property = "IsSelected" Value = "{Binding IsSelected, Mode=TwoWay}"/>
    <Setter Property = "Tag" Value = "{Binding}"/>
    <Style.Triggers>
        <DataTrigger Binding = "{Binding Path=IsVisible}" Value = "False">
            <Setter Property = "Visibility" Value = "Collapsed"/>
        </DataTrigger>
        <Trigger Property = "beh:TreeNodeMouseOver.IsMouseDirectlyOverItem" Value = "True">
            <Setter Property = "Background" Value = "AliceBlue" />
        </Trigger>
    </Style.Triggers>
</Style>

XAML для ContextMenu:

<ContextMenu x:Key = "MenuItemContextMenu" ItemsSource = "{Binding RelativeSource = {RelativeSource Mode=FindAncestor, AncestorType=Window}, Path=TreeViewModel.MenuItems, UpdateSourceTrigger=PropertyChanged}">
    <ContextMenu.ItemTemplate>
        <HierarchicalDataTemplate DataType = "{x:Type model:MenuItemBaseViewModel}" ItemsSource = "{Binding Path=SubItems, UpdateSourceTrigger=PropertyChanged}">
            <TextBlock Text = "{Binding Header}"/>
        </HierarchicalDataTemplate>
    </ContextMenu.ItemTemplate>
    <ContextMenu.ItemContainerStyle>
        <Style TargetType = "MenuItem">
            <Setter Property = "ToolTip" Value = "{Binding ToolTip}"/>
            <Setter Property = "IsHitTestVisible" Value = "True"/>
            <Setter Property = "IsEnabled" Value = "{Binding IsEnabled}"/>
            <Setter Property = "Command" Value = "{Binding MouseLeftButtonDownCommand}"/> <!--LeftClick is bound to ViewModel here, but RightClick is not even defined anywhere in MenuItem or ViewModel-->
            <Style.Triggers>
                <DataTrigger Binding = "{Binding VisibleSubItems}" Value = "0">
                    <Setter Property = "Template">
                        <Setter.Value>
                            <ControlTemplate TargetType = "{x:Type MenuItem}">
                                <Border x:Name = "templateRoot" BorderBrush = "{TemplateBinding BorderBrush}" BorderThickness = "{TemplateBinding BorderThickness}" Background = "{TemplateBinding Background}" SnapsToDevicePixels = "True">
                                    <Grid Margin = "-1">
                                        <Grid.ColumnDefinitions>
                                            <ColumnDefinition MinWidth = "22" SharedSizeGroup = "MenuItemIconColumnGroup" Width = "Auto"/>
                                            <ColumnDefinition Width = "13"/>
                                            <ColumnDefinition Width = "*"/>
                                            <ColumnDefinition Width = "20"/>
                                            <ColumnDefinition SharedSizeGroup = "MenuItemIGTColumnGroup" Width = "Auto"/>
                                            <ColumnDefinition Width = "Auto"/>
                                            <ColumnDefinition Width = "Auto" />
                                        </Grid.ColumnDefinitions>
                                        <ContentPresenter x:Name = "Icon" Content = "{TemplateBinding Icon}" ContentSource = "Icon" HorizontalAlignment = "Center" Height = "16" Margin = "3" SnapsToDevicePixels = "{TemplateBinding SnapsToDevicePixels}" VerticalAlignment = "Center" Width = "16"/>
                                        <Border x:Name = "GlyphPanel" BorderBrush = "#FF26A0DA" BorderThickness = "1" Background = "#3D26A0DA" ClipToBounds = "False" HorizontalAlignment = "Center" Height = "22" Margin = "-1,0,0,0" Visibility = "Hidden" VerticalAlignment = "Center" Width = "22">
                                            <Path x:Name = "Glyph" Data = "F1M10,1.2L4.7,9.1 4.5,9.1 0,5.2 1.3,3.5 4.3,6.1 8.3,0 10,1.2z" Fill = "#FF212121" FlowDirection = "LeftToRight" Height = "11" Width = "10"/>
                                        </Border>
                                        <ContentPresenter x:Name = "menuHeaderContainer" ContentTemplate = "{TemplateBinding HeaderTemplate}" Content = "{TemplateBinding Header}" Grid.Column = "2" ContentStringFormat = "{TemplateBinding HeaderStringFormat}" ContentSource = "Header" HorizontalAlignment = "Left" Margin = "{TemplateBinding Padding}" RecognizesAccessKey = "True" SnapsToDevicePixels = "{TemplateBinding SnapsToDevicePixels}" VerticalAlignment = "Center"/>
                                        <TextBlock x:Name = "menuGestureText" Grid.Column = "4" Margin = "{TemplateBinding Padding}" Opacity = "0.7" Text = "{TemplateBinding InputGestureText}" VerticalAlignment = "Center"/>
                                        <Button Grid.Column = "5" Margin = "2" Command = "{Binding EditCommand}" Visibility = "{Binding IsEditVisible, Converter = {StaticResource BooleanToVisibilityConverter}}" Background = "Transparent" BorderThickness = "0">
                                            <iconPacks:PackIconMaterialLight Width = "14" Height = "14" Foreground = "Black" HorizontalAlignment = "Center" VerticalAlignment = "Center" Kind = "Cog" />
                                        </Button>
                                        <Button Grid.Column = "6" Margin = "2" Command = "{Binding HelpCommand}" Visibility = "{Binding IsInfoVisible, Converter = {StaticResource BooleanToVisibilityConverter}}" Background = "Transparent" BorderThickness = "0">
                                            <iconPacks:PackIconMaterial  Width = "14" Height = "14" Foreground = "Blue" HorizontalAlignment = "Center" VerticalAlignment = "Center" Kind = "InformationOutline" />
                                        </Button>
                                    </Grid>
                                </Border>
                                <ControlTemplate.Triggers>
                                    <Trigger Property = "Icon" Value = "{x:Null}">
                                        <Setter Property = "Visibility" TargetName = "Icon" Value = "Collapsed"/>
                                    </Trigger>
                                    <Trigger Property = "IsChecked" Value = "True">
                                        <Setter Property = "Visibility" TargetName = "GlyphPanel" Value = "Visible"/>
                                        <Setter Property = "Visibility" TargetName = "Icon" Value = "Collapsed"/>
                                    </Trigger>
                                    <Trigger Property = "IsHighlighted" Value = "True">
                                        <Setter Property = "Background" TargetName = "templateRoot" Value = "#3D26A0DA"/>
                                        <Setter Property = "BorderBrush" TargetName = "templateRoot" Value = "#FF26A0DA"/>
                                    </Trigger>
                                    <Trigger Property = "IsEnabled" Value = "False">
                                        <Setter Property = "TextElement.Foreground" TargetName = "templateRoot" Value = "#FF707070"/>
                                        <Setter Property = "Fill" TargetName = "Glyph" Value = "#FF707070"/>
                                    </Trigger>
                                    <MultiTrigger>
                                        <MultiTrigger.Conditions>
                                            <Condition Property = "IsHighlighted" Value = "True"/>
                                            <Condition Property = "IsEnabled" Value = "False"/>
                                        </MultiTrigger.Conditions>
                                        <Setter Property = "Background" TargetName = "templateRoot" Value = "#0A000000"/>
                                        <Setter Property = "BorderBrush" TargetName = "templateRoot" Value = "#21000000"/>
                                    </MultiTrigger>
                                </ControlTemplate.Triggers>
                            </ControlTemplate>
                        </Setter.Value>
                    </Setter>
                </DataTrigger>
                <DataTrigger Binding = "{Binding IsVisible}" Value = "false">
                    <Setter Property = "MenuItem.Visibility" Value = "Collapsed"/>
                </DataTrigger>
                <DataTrigger Binding = "{Binding PackIcon.IconType}" Value = "{x:Type iconPacks:PackIconSimpleIconsKind}">
                    <Setter Property = "MenuItem.Icon" Value = "{StaticResource Simple}"/>
                </DataTrigger>
                <DataTrigger Binding = "{Binding PackIcon.IconType}" Value = "{x:Type iconPacks:PackIconEntypoKind}">
                    <Setter Property = "MenuItem.Icon" Value = "{StaticResource Entypo}"/>
                </DataTrigger>
                <DataTrigger Binding = "{Binding PackIcon.IconType}" Value = "{x:Type iconPacks:PackIconFontAwesomeKind}">
                    <Setter Property = "MenuItem.Icon" Value = "{StaticResource FontAwesome}"/>
                </DataTrigger>
                <DataTrigger Binding = "{Binding PackIcon.IconType}" Value = "{x:Type iconPacks:PackIconMaterialKind}">
                    <Setter Property = "MenuItem.Icon" Value = "{StaticResource Material}"/>
                </DataTrigger>
                <DataTrigger Binding = "{Binding PackIcon.IconType}" Value = "{x:Type iconPacks:PackIconMaterialLightKind}">
                    <Setter Property = "MenuItem.Icon" Value = "{StaticResource MaterialLight}"/>
                </DataTrigger>
                <DataTrigger Binding = "{Binding PackIcon.IconType}" Value = "{x:Type iconPacks:PackIconModernKind}">
                    <Setter Property = "MenuItem.Icon" Value = "{StaticResource Modern}"/>
                </DataTrigger>
                <DataTrigger Binding = "{Binding PackIcon.IconType}" Value = "{x:Type iconPacks:PackIconOcticonsKind}">
                    <Setter Property = "MenuItem.Icon" Value = "{StaticResource Octicons}"/>
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </ContextMenu.ItemContainerStyle>
    <i:Interaction.Behaviors>
        <beh:EventToCommandBehavior Command = "{Binding RelativeSource = {RelativeSource Mode=FindAncestor, AncestorType=Window}, Path=TreeViewModel.ContextMenuOpenedCommand}" Event = "Opened" PassArguments = "True" />
    </i:Interaction.Behaviors>
</ContextMenu>