Window.xaml

<Window x:Class="WpfFocusScopeTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525" Loaded="Window_Loaded">
    <Window.CommandBindings>
        <CommandBinding Command="Paste" x:Name="bindingPaste" PreviewCanExecute="bindingPaste_PreviewCanExecute" />
    </Window.CommandBindings>
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" /><RowDefinition Height="Auto"  /><RowDefinition />
        </Grid.RowDefinitions>
        
        <Menu>
            <MenuItem Header="Edit"><MenuItem Command="Paste" Name="menuItemPaste"/></MenuItem>
        </Menu>
        
        <ToolBarTray Grid.Row="1">
            <ToolBar Band="0" BandIndex="0">
                <Button Command="Paste" Name="buttonPaste">Paste</Button>
            </ToolBar>
            <ToolBar Band="0" BandIndex="1">
                <TextBox Width="100" />
            </ToolBar>
        </ToolBarTray>

        <DockPanel Grid.Row="2">
            <TextBox />
        </DockPanel>

    </Grid>
</Window>