How can I use datatable selection in dialog widget in PrimeFaces? - jsf

Question

I am trying to use datatable selection in dialog widget. But I cannot get selected value in my bean. Datatable selection is working, if I delete dialog widget tag. I am using PrimeFaces 4.0. How can I fix this?
passengerform.xhtml
<p:hotkey bind="esc" handler="dialogWidget.hide();" />
<p:dialog id="dialog" widgetVar="dialogWidget"
header="Coupon List" modal="true" width="400" showEffect="fade"
hideEffect="fade" appendTo="#(body)">
<h:form id="formDialog">
<h:outputLabel value="Lütfen E-ticket Kuponunu Seçiniz." />
<p:dataTable id="singleDT" var="coupon"
value="#{passengerFormService.couponList}"
rowKey="#{coupon.id}" rowIndexVar="rowIndex"
selection="#{passengerFormService.selectedCoupon}"
selectionMode="single">
<p:ajax event="rowSelect"
listener="#{passengerFormService.selectCoupon}"
update=":tab1:tab1_1:eticketform:formDialog">
<f:setPropertyActionListener value="#{coupon}"
target="#{passengerFormService.coupon}" />
</p:ajax>
<f:facet name="header"></f:facet>
<h:inputHidden name="hidden1"
value="#{passengerFormService.passengerForm.id}" />
<p:column style="width:20px" width="20">
<f:facet name="header">
<h:outputText value="#" />
</f:facet>
<h:outputText value="#{rowIndex+1}" />
</p:column>
<p:column headerText="Id">
<h:outputText value="#{coupon.id}" />
</p:column>
<p:column headerText="Departure Location">
<h:outputText value="#{coupon.departureLocation}" />
</p:column>
<f:facet name="footer"></f:facet>
</p:dataTable>
<p:separator />
<h:panelGrid columns="2" cellspacing="5"
columnClasses="alignLeft,alignRight" style="width:100%">
<p:commandButton id="selectButton1" update=""
icon="ui-icon-close" value="İptal"
oncomplete="PF('dialogWidget').hide()" />
<p:commandButton id="cancelSelectedButton1"
update=":tab1:tab1_1:passengerInsertform"
icon="ui-icon-check"
value="Onayla" oncomplete="PF('dialogWidget').hide()" />
</h:panelGrid>
</h:form>
</p:dialog>
PassengerFormService.java
public void selectCoupon(SelectEvent event) {
Log.getLogger().debug("New2 coupon selected...");
Log.getLogger().debug("selected: " +getSelectedCoupon());
}