var currentGroup = '';
function showGroup(source) {
	var list = Array('group1', 'group2','group3','group4');
	var element;
	var currentId;
	
	if (source) if (source.className == 'group') currentId = source.id; else currentId = source.id.substr(7);
	for (var x in list) {
		element = document.getElementById(list[x]);
		element2 = document.getElementById('column-' + list[x])
		if (!element || !element2) continue;
		if (element.id == currentId) {
			element.className = 'group-current';
			element2.style.display = 'block';
			currentGroup = list[x];
		} else {
			element.className = 'group';
			element2.style.display = 'none';
		}
	}
	element = document.getElementById('column-default');
	if (!source) {
		element.style.display = 'block';
	} else {
		element.style.display = 'none';
	}
}