The selected item in a WPF TreeView has a dark blue background with "sharp" corners. That looks a bit dated today:

I would like to change the background to look like in Explorer of Windows 7 (with/without focus):

What I tried so far does not remove the original dark blue background but paints a rounded border on top of it so that you see the dark blue color at the edges and at the left side - ugly.

Interestingly, when my version does not have the focus, it looks pretty OK:

I would like to refrain from redefining the control template as shown here or here. I want to set the minimum required properties to make the selected item look like in Explorer.

Alternative: I would also be happy to have the focused selected item look like mine does now when it does not have the focus. When losing the focus, the color should change from blue to grey.

Here is my code:

<TreeView 
    x:Name="TreeView"
    ItemsSource="{Binding TopLevelNodes}" 
    VirtualizingStackPanel.IsVirtualizing="True"
    VirtualizingStackPanel.VirtualizationMode="Recycling">

    <TreeView.ItemContainerStyle>
        <Style TargetType="{x:Type TreeViewItem}">
            <Setter Property="IsExpanded" Value="{Binding IsExpanded, Mode=TwoWay}" />
            <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />

            <Style.Triggers>
                <Trigger Property="IsSelected" Value="True">
                    <Setter Property="BorderBrush" Value="#FF7DA2CE" />
                    <Setter Property="Background" Value="#FFCCE2FC" />
                </Trigger>
            </Style.Triggers>
        </Style>
    </TreeView.ItemContainerStyle>

    <TreeView.Resources>
        <HierarchicalDataTemplate DataType="{x:Type viewmodels:ObjectBaseViewModel}" ItemsSource="{Binding Children}">
            <Border Name="ItemBorder" CornerRadius="2" Background="{Binding Background, RelativeSource={RelativeSource AncestorType=TreeViewItem}}"
                      BorderBrush="{Binding BorderBrush, RelativeSource={RelativeSource AncestorType=TreeViewItem}}" BorderThickness="1">
                <StackPanel Orientation="Horizontal" Margin="2">
                    <Image Name="icon" Source="/ExplorerTreeView/Images/folder.png"/>
                    <TextBlock Text="{Binding Name}"/>
                </StackPanel>
            </Border>
        </HierarchicalDataTemplate>
    </TreeView.Resources>
</TreeView>