Why ItemsControl.ToolTip is visible only if mouse over its item
===

Here the problem. I have an **ItemsControl**, and I want to show a **ToolTip** if user hover mouse over **ItemsControl**. Seems easy, right?

Here an example:

    <ItemsControl BorderBrush="Blue" BorderThickness="1">
        <ItemsControl.ToolTip>
            <ToolTip Content="Text" />
        </ItemsControl.ToolTip>
        <ItemsControl.ItemsPanel>
            <ItemsPanelTemplate>
                <WrapPanel />
            </ItemsPanelTemplate>
        </ItemsControl.ItemsPanel>
        <Label BorderBrush="Red" BorderThickness="1">One</Label>
        <Label BorderBrush="Red" BorderThickness="1">Two</Label>
        <Label BorderBrush="Red" BorderThickness="1">Three</Label>
        <Label BorderBrush="Red" BorderThickness="1">Four</Label>
        <Label BorderBrush="Red" BorderThickness="1">Five</Label>
        <Label BorderBrush="Red" BorderThickness="1">Six</Label>
        <Label BorderBrush="Red" BorderThickness="1">Seven</Label>
    </ItemsControl>

Make window width small enough, and let **WrapPanel** to wrap an items. And try to hover over **ItemsControl** (**ToolTip** will not appears), than hover over **Label** (**ToolTip** will appears).

Why this behavior is right and how to force **ToolTip** to appears in this case?