Menu item blows up when it's on a top level window.

[tomlm]

Change Gallery ControlsListView.xaml to look like this:

    <Grid RowDefinitions="Auto *">
        <Menu>
            <MenuItem Header="_File">
                <MenuItem Header="E_xit" Click="Exit_Click"/>
            </MenuItem>
        </Menu>

        <DockPanel Grid.Row="1">

            <Grid RowDefinitions="* Auto" DockPanel.Dock="Left">
                <DataGrid x:Name="Grid"
                          SelectedIndex="0"
                          SelectionMode="Single">
                    <DataGrid.Columns>
                        <DataGridTextColumn Header="Name"
                                            Binding="{Binding Name}" />
                    </DataGrid.Columns>
                </DataGrid>
                <Button Grid.Row="1" Content="Exit" Click="Exit_Click" KeyboardNavigation.IsTabStop="False"/>
            </Grid>
            <Border Child="{Binding ElementName=Grid,Path=SelectedItem, Converter={StaticResource GalleryItemConverter}}"
                    BorderThickness="1"
                    BorderBrush="{DynamicResource ThemeBorderBrush}" />
        </DockPanel>
    </Grid>

All I did was add a menu with a submenu.

Repo steps:

1. click on File menu
2. Click anywhere away from the File menu to cancel the menu.
   It blows with an exception inside TurboVision Menu extension.