WPF 右键菜单，绑定命令后，按钮不可用

Question

xamal文件，我尝试在toolBar、Menu、ContextMenu中绑定命令，在toolBar、Menu中都正常，为什么只有右键菜单（ContextMenu)的两个按钮为何不能点？代码如下<Window x:Class="_1.命令入门.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/up-compatibility/2006"
        xmlns:local="clr-namespace:_1.命令入门"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Window.CommandBindings>
        <CommandBinding Command="ApplicationCommands.Open"
            Executed="OpenCommand_Exexuted"></CommandBinding>
        <CommandBinding Command="ApplicationCommands.New"
            Executed="NewCommand_Exexuted"></CommandBinding>
    </Window.CommandBindings>    <Window.ContextMenu>
        <ContextMenu>
            <MenuItem Header="新建" Command="ApplicationCommands.New"></MenuItem>
            <MenuItem Header="打开" Command="ApplicationCommands.Open"></MenuItem>
        </ContextMenu>
    </Window.ContextMenu>
    <StackPanel>
        <Menu>
            <MenuItem Header="文件">
                <MenuItem Header="新建" Command="ApplicationCommands.New"></MenuItem>
                <MenuItem Header="打开" Command="ApplicationCommands.Open"></MenuItem>
            </MenuItem>
        </Menu>        <ToolBar>
            <Button Command="ApplicationCommands.New">新建</Button>
            <Button Command="ApplicationCommands.Open">打开</Button>
        </ToolBar>
    </StackPanel>
</Window>

Answer 1

知道怎么解决了，给右键菜单的command设置CommandTarget    <Window.ContextMenu>
        <ContextMenu>
            <MenuItem Header="新建" Command="ApplicationCommands.New" CommandTarget="{Binding ElementName=cbBox_Mode}"></MenuItem>
            <MenuItem Header="打开" Command="ApplicationCommands.Open"></MenuItem>
        </ContextMenu>
    </Window.ContextMenu>

Answer 2

参考：《WPF 编程宝典:使用C# 2012和.net 4.5 第四版》 P227