For very large Form-UIs it is a good help to comment parts of it.
Comments always start with <!-- and end with -->. In between may lie a few comments, but also entire program sections.
<!-- Dies ist eine Kommentarzeile -->
<!-- Die folgende Tabelle ist auskommentiert
<table columns="2"
..<td> ? </td>
..<td> ? </td>
..<td> ? </td>
..<td> ? </td>
</table>
-->