Primefaces selectOneMenu with converter

pf_selectonemenu_converter.jsp

<p:column id="recipientName" headerText="Recipient" sortBy="#{t.recipient}" filterBy="#{t.recipient}">
    <p:cellEditor>
        <f:facet name="output">
            <h:outputText value="#{t.recipient.firstname} #{t.recipient.lastname}"/>
        </f:facet>
        <f:facet name="input">
            <p:selectOneMenu value="#{t.recipient}" converter="recipient">
                <f:selectItem itemLabel="Select One" itemValue=""/>
                <f:selectItems value="#{userBean.users}" var="recipient" itemLabel="#{recipient.username}" itemValue="#{recipient.username}"/>
            </p:selectOneMenu>
        </f:facet>
    </p:cellEditor>
</p:column>