The elementFormDefault can be qualified or unqualified, unqualified is the default. "qualified" means that all the local elements(such as shipTo below) must be qualified, either through specified namespace or default namespace. Example: po.xsd as:
.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, “Courier New”, courier, monospace;
background-color: [...]