XAML ListView Items IsEnabled - wpf

Question

I have the following XAML :
<Grid Grid.Row="3" Margin="8,8">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<!-- Setting 'UsingItems' here -->
<CheckBox Grid.Row="0"
IsChecked="{Binding Path=UsingItems}"
Content="{Binding Path=IncludeItemsText}" />
<!-- This works as expected -->
<CheckBox Grid.Row="1"
IsEnabled="{Binding Path=UsingItems}"/>
<!-- This doesn't! Even though the ListView becomes enabled the Items aren't and the Checkboxes are not checkable! -->
<ListView Grid.Row="2" IsEnabled="{Binding Path=UsingItems}"
VerticalAlignment="Stretch"
ItemsSource="{Binding Path=SortedItems}">
<ListView.ItemTemplate>
<DataTemplate>
<DockPanel>
<CheckBox
IsChecked="{Binding Path=.IsSelected}"
Margin="0,2" Click="CheckBox_Click" />
<TextBlock
Text="{Binding Path=.Item.ItemDescription}"
Margin="4,0,0,0"
VerticalAlignment="Top">
</TextBlock>
</DockPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</Grid>
I would like to Disable all Items in the ListView if the property 'UsingItems' = false. 'UsingItems' is set using the Checkbox in Row 0, I've confirmed this is working by having a dummy Checkbox in Row 1 - the 'IsEnabled' property is set as expected.
However, the ListView Items remain disabled when 'UsingItems' = true, even though the ListView becomes enabled (and the items 'look' enabled).
I had assumed the IsEnabled property would filter down the tree - but this is not happening here.
Where am I going wrong?
Thanks
Joe