C# RibbonControl库中的问题

我在Microsoft的RibbonControl库中面临一个问题。我已经创建了一个简单的WPF应用程序，我正在使用RibbonControlLibrary在顶部创建一个功能区栏。问题如下图所示

问题是“打开”菜单下的菜单只能扩展到左侧菜单中的项目，即项目1、项目2。。。如果我在左菜单中增加一个项目，我会得到这个

但菜单中的某些项下缺少窗台项目

下面是我正在使用的XAML

 <Ribbon:Ribbon ItemsSource="{Binding Path=CSIMRibbonTabs}">
            <Ribbon:Ribbon.ApplicationMenu>
                <Ribbon:RibbonApplicationMenu CanUserResizeVertically="True" ItemsSource="{Binding Path=MainItem}">
                    <Ribbon:RibbonApplicationMenu.AuxiliaryPaneContent>
                        <Grid> 
                            <Grid.RowDefinitions>
                                <RowDefinition />
                                <RowDefinition Height="*"/>
                            </Grid.RowDefinitions>
                            <Border  >
                                <StackPanel  Orientation="Vertical">
                                    <Label Content="Something"  />
                                </StackPanel>
                            </Border>
                            <ItemsControl  Grid.Row="1" ItemsSource="{Binding Path=OtherItems}"/>
                        </Grid>
                    </Ribbon:RibbonApplicationMenu.AuxiliaryPaneContent>
                </Ribbon:RibbonApplicationMenu>
            </Ribbon:Ribbon.ApplicationMenu>
        </Ribbon:Ribbon>

代码

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我应该怎么做才能在列表中的项目下展开菜单？

尝试向网格元素添加以下属性： ScrollViewer.VerticalScrollBarVisibility=自动

                <Ribbon:RibbonApplicationMenu.AuxiliaryPaneContent> 
                    <Grid ScrollViewer.VerticalScrollBarVisibility="Auto">  
                        <Grid.RowDefinitions> 
                            <RowDefinition /> 
                            <RowDefinition Height="*"/> 
                        </Grid.RowDefinitions> 
                        <Border  > 
                            <StackPanel  Orientation="Vertical"> 
                                <Label Content="Something"  /> 
                            </StackPanel> 
                        </Border> 
                        <ItemsControl  Grid.Row="1" ItemsSource="{Binding Path=OtherItems}"/> 
                    </Grid> 
                </Ribbon:RibbonApplicationMenu.AuxiliaryPaneContent> 

                <Ribbon:RibbonApplicationMenu.AuxiliaryPaneContent> 
                    <Grid ScrollViewer.VerticalScrollBarVisibility="Auto">  
                        <Grid.RowDefinitions> 
                            <RowDefinition /> 
                            <RowDefinition Height="*"/> 
                        </Grid.RowDefinitions> 
                        <Border  > 
                            <StackPanel  Orientation="Vertical"> 
                                <Label Content="Something"  /> 
                            </StackPanel> 
                        </Border> 
                        <ItemsControl  Grid.Row="1" ItemsSource="{Binding Path=OtherItems}"/> 
                    </Grid> 
                </Ribbon:RibbonApplicationMenu.AuxiliaryPaneContent>