How to change the colors of the winforms treeview after SetWindowTheme has been applied

I have a windows forms treeview. The default plus minus icons of the treeview are not updated with the Windows 7 styles.

To achieve that I have used the SetWindowTheme from UXTheme.dll

SetWindowTheme(tvwRoot.Handle, "explorer", null);

After applying this, I am unable to change the selectednode color of the treeview. I tried the following,

private void tvwRoot_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
    {

        if (tvwRoot.GetNodeAt(e.Location) != null)
        {
            tvwRoot.SelectedNode = tvwRoot.GetNodeAt(e.Location);

            tvwRoot.SelectedNode.BackColor = System.Drawing.Color.FromArgb(51, 153, 255);
            tvwRoot.SelectedNode.ForeColor = System.Drawing.Color.White;

            if (e.Button == MouseButtons.Right)
            {
                nodRightClick = tvwRoot.SelectedNode;
                blnRightClick = true;
                pntLocation = e.Location;
            }
        }
        else
        {
            tvwRoot.SelectedNode = null;
            nodRightClick = null;
        }

    }

    private void tvwRoot_MouseUp(object sender, System.Windows.Forms.MouseEventArgs e)
    {
        if (tvwRoot.SelectedNode != null)
        {
            if (tnPreviousSelected != null && !tnPreviousSelected.FullPath.Equals(tvwRoot.SelectedNode.FullPath))
                tnPreviousSelected = tvwRoot.SelectedNode;
            else if (tnPreviousSelected == null)
                tnPreviousSelected = tvwRoot.SelectedNode;


            tvwRoot.SelectedNode.BackColor = System.Drawing.Color.FromArgb(51, 153, 255);
            tvwRoot.SelectedNode.ForeColor = System.Drawing.Color.White;
        }

    }

    private void tvwRoot_AfterSelect(object sender, TreeViewEventArgs e)
    {
        if (tnPreviousSelected != null && !tnPreviousSelected.FullPath.Equals(tvwRoot.SelectedNode.FullPath))
        {
            tnPreviousSelected.BackColor = tvwRoot.BackColor;
            tnPreviousSelected.ForeColor = tvwRoot.ForeColor;
            tnPreviousSelected = null;
        }

        if (tvwRoot.SelectedNode != null)
        {
            if (tnPreviousSelected != null && !tnPreviousSelected.FullPath.Equals(tvwRoot.SelectedNode.FullPath))
                tnPreviousSelected = tvwRoot.SelectedNode;
            else if (tnPreviousSelected == null)
                tnPreviousSelected = tvwRoot.SelectedNode;

            tvwRoot.SelectedNode.BackColor = System.Drawing.Color.FromArgb(51, 153, 255);
            tvwRoot.SelectedNode.ForeColor = System.Drawing.Color.White;
        }
    }

But with this the color appears on the treeview after the focus is removed from the treeview. Is there any way to change the color after SetWindowTheme has been applied?