function ToggleTreeListHeader(elemenID, iconID)
{
	var TreeNode = document.getElementById(elemenID);
	var TreeNodeIcon = document.getElementById(iconID);

if(TreeNode.style.display=='block')
	{
		TreeNode.style.display = 'none';
		TreeNodeIcon.src='/images/navtree_plus_sign.gif';
	}
    else
	{
		TreeNode.style.display = 'block';
		TreeNodeIcon.src='/images/navtree_minus_sign.gif';
	}
}