function displaySubMenu(group,img_name)
{
	var row = document.getElementById(group);
	if (row.style.display == '') row.style.display = 'none';
	else row.style.display = '';
	var img_name_folded = img_name + 'folded'; 
	var img_name_unfolded = img_name + 'unfolded';
	if (document.getElementById(img_name_folded).style.display == '') 
	{ 
		document.getElementById(img_name_folded).style.display = 'none';
		document.getElementById(img_name_unfolded).style.display = '';
	}
	else 
	{ 
		document.getElementById(img_name_folded).style.display = '';
		document.getElementById(img_name_unfolded).style.display = 'none';
	}
}