When I select the menu item 'Minimize the ribbon' from the Quick Access Toolbar the grid below the ribbon does not resize to fill the space.  The space where the ribbon was is now black.  How do I get the grid to resize when the ribbon is minimized?

<igRibbon:XamRibbonWindow x:Class="TaskScheduler.MainWindow"
    xmlns:app="clr-namespace:TaskScheduler"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:igThemes="http://infragistics.com/Themes"
    Title="Window1" Height="471" Width="859" Loaded="Window_Loaded" xmlns:igRibbon="http://infragistics.com/Ribbon">
    <igRibbon:RibbonWindowContentHost>
        <igRibbon:RibbonWindowContentHost.Ribbon>
            <igRibbon:XamRibbon Height="85" Name="xamRibbon1" Theme="Office2k7Blue">
                <igRibbon:XamRibbon.ApplicationMenu>
                    <igRibbon:ApplicationMenu />
                </igRibbon:XamRibbon.ApplicationMenu>
                <igRibbon:XamRibbon.QuickAccessToolbar>
                    <igRibbon:QuickAccessToolbar />
                </igRibbon:XamRibbon.QuickAccessToolbar>
            </igRibbon:XamRibbon>
        </igRibbon:RibbonWindowContentHost.Ribbon>
        <Grid Width="Auto" Height="Auto">
            <Grid.RowDefinitions>
                <RowDefinition Height="30"/>
            </Grid.RowDefinitions>
            <TextBox HorizontalAlignment="Left" Margin="52,10,0,-3" Name="textBox1" Width="283" />
        </Grid>
    </igRibbon:RibbonWindowContentHost>
</igRibbon:XamRibbonWindow>