The email publisher lets support agents who use Case Feed compose and send email messages to customers. You can customize this publisher to support email templates and attachments. This component can only be used in organizations that have Case Feed and Email-to-Case enabled. Ext JS versions less than 3 should not be included on pages that use this component.

An area of a Visualforce page that demarcates which components should be processed by the Force.com server when an AJAX request is generated. Only the components in the body of the <apex:actionRegion> are processed by the server, thereby increasing the performance of the page.

A link that executes an action defined by a controller, and then either refreshes the current page, or navigates to a different page based on the PageReference variable that is returned by the action. An <apex:commandLink> component must always be a child of an <apex:form> component.To add request parameters to an <apex:commandLink>, use nested <apex:param> components.

A timer that sends an AJAX update request to the server according to a time interval that you specify. The update request can then result in a full or partial page update. You should avoid using this component with enhanced lists.

A single column in a table. An <apex:column> component must always be a child of an <apex:dataTable> or <apex:pageBlockTable> component.

Note: that if you specify an sObject field as the value attribute for an <apex:column>, the associated label for that field is used as the column header by default. To override this behavior, use the headerValue attribute on the column, or the column's header facet.