ListBox Background Color (XAML/WinRT/Metro)

Question

I'm trying to change the background color on a "ListBox" on a WinRT page (XAML). When I use the "Background" property, it changes the background how I want it when the control doesn't have the focus. When it gets the focus, it changes to White and I can't figure out how to override it.

My question, how to I force the background of the ListBox to always be Gray whether it's selected/has focus or not?

XAML #1:

    <ListBox x:Name="ListBoxMenu" Background="LightGray" Grid.Row="0" Grid.Column="0" Margin="0,0,0,0">
        <ListBoxItem>Menu Item 1</ListBoxItem>
        <ListBoxItem>Menu Item 2</ListBoxItem>
        <ListBoxItem>Menu Item 3</ListBoxItem>
    </ListBox>

XAML #2 (with each item also set):

    <ListBox x:Name="ListBoxMenu" Background="LightGray" Grid.Row="0" Grid.Column="0" Height="124" VerticalAlignment="Top">
        <ListBoxItem Background="LightGray">Menu Item 1</ListBoxItem>
        <ListBoxItem Background="LightGray">Menu Item 2</ListBoxItem>
        <ListBoxItem Background="LightGray">Menu Item 3</ListBoxItem>
    </ListBox>

As temporary solution, I set the ListBox to only be a hard coded height, then used a border on that column to fill in the rest of the space with LightGray. I really would like to just always set the Background color on the ListBox though, is this possible?