If a custom content class is registered on a folder and a custom form is registered for that content class, when a user creates a new item in that folder, a new browser window opens, and the custom form is called. When the user reads, replies to, or performs other actions on the item, the registered form is displayed. You can register forms by creating correctly formatted ElementClass and Mapping (Forms Registry XML Element) entries in the ApplicationElement section of a registry.xml file. The following example shows the XML for the mapping of three custom forms to different actions on items of the type IPM.MyContentClass.

<ApplicationElement Name="Item">
    <ElementClass Value="IMP.MyContentClass">
        <Mapping 
            Form="http://server/mycontentclassopen.aspx"/>
        <Mapping Action="Open" State="Draft" 
            Form="http://server/mycontentclassedit.aspx"/>
        <Mapping Action="Forward"
            Form="http://server/mycontentclassforward.aspx"/>
        <Mapping Action="Print"
            Form="http://server/mycontentclassprint.aspx"/>
    </ElementClass>
</ApplicationElement>