how to show selected node custom treeview in wpf

I have custom treeview in wpf

<treeview grid.row="0" grid.column="0" name="ApplicationTree" datacontext="{Binding}" itemssource="{Binding Master}" itemtemplate="{StaticResource MasterTemplate}" borderbrush="Black" borderthickness="3,3,3,3" height="500">

<datatemplate x:key="DetailTemplate" xmlns:x="#unknown">
            <canvas height="30">
                <Image Source="{Binding Imageurl}" Width="25" Height="25" VerticalAlignment="Center"/>
                <Label Name="lblDetailTree"  Content="{Binding Info}" FontSize="15" Canvas.Top="0" Canvas.Left="30" MouseDown="lblDetailTree_MouseDown" MouseUp="lblDetailTree_MouseUp" />
            </canvas>
        </datatemplate>

private void lblDetailTree_MouseUp(object sender, MouseButtonEventArgs e)
        {
            System.Windows.Controls.Label lblnode = (System.Windows.Controls.Label)sender;
            lblnode.Background = Brushes.CadetBlue;
        }


</treeview>

when i select node, i get selected node label,then i change color of selected node & its changing..but when i selected another node then i want to change color of previously selected node back to its old style.

need help asap..thanks in advance.

Tags: C# 3.5