I'm learning about Prado Framework. I don't know why my code won't run when it doesn't have TForm and THead. The tutorial on Prado framework site didn't say anything about it. When I delete THead the page shows an error. When I delete TForm I can't change between view1 view2 and view 3. 
Here is the code

```
<html>
<head><title>Welcome to PRADO</title></head>
<body>

<com:THead>
<com:TForm>
    <com:TAccordion ActiveViewID="View2">
    <com:TAccordionView ID="View1" Caption="View 1" >
        <h2>View 1</h2>
    </com:TAccordionView>

    <com:TAccordionView ID="View2" Caption="View 2">
        <h2>View 2</h2>
    </com:TAccordionView>

    <com:TAccordionView Caption="View 3">
        <h2>View 3</h2>
    </com:TAccordionView>
    </com:TAccordion>
</com:TForm>
</com:THead>

</body>
</html>

```

Thanks you.