var osel = selection ;

for(var i = 0 ; i<osel.count ; i++)
	{
	var ovs = osel(i).properties("visibility").selectability.Value ;

	if (ovs == 0)
		{
		osel(i).properties("visibility").selectability.value = "True" ;
		}
	else
		{
		osel(i).properties("visibility").selectability.value = "False" ;
		}
	}