Primefaces cant fill inputText in dialog after click contextmenu - jsf

Question

I'm using Primefaces Datatable-ContextMenu and Dialog to update a row (When after click to contextmenu it opens a dialog which contains will update object's fields in <p:inputext />).
I have tried dynamic true, initilazing object on constructor because when page is rendered selectedObject will be null in dialog and when I tried to use it gives null pointer exception so that i need other advices.
Here is ContextMenu:
<p:contextMenu for="functions" id="functionContextMenu">
<p:menuitem value="Guncelle" icon="ui-icon-" update="updateDialog" oncomplete="updateDialog.show()"/>
And my dialog is here:
<p:dialog header="Guncelle" widgetVar="updateDialog" resizable="false"
width="200" showEffect="clip" hideEffect="fold" id="updateDialog" dynamic="true">
<h:panelGroup id="display">
<h:outputText value="#{functionControllerBean.selectedFunction.functionName}" />
<h:inputText id="firstName" value="{functionControllerBean.tempSelectedFunction1.functionName}" />
</h:panelGroup>
</p:dialog>
If I dont use <p:inputText /> its ok and show what i put <h:outputText /> but when i put p:inputext inside of dialog;it doesnt show output text value and shows <p:inputText /> empty even its not.
I had used beanname.objectname.field before inside of <p:inputText /> or <h:inputText /> but there was no problem but now it's not working.
And here is my ManagedBean :
#ManagedBean
#RequestScoped
public class FunctionControllerBean implements Serializable {
private EfaFunctions willAddFunction;
private EfaFunctions selectedFunction = new EfaFunctions();
Thanks in advance
UPDATE Here is page
<h:form id="form">
<p:contextMenu for="functions" id="functionContextMenu">
<p:menuitem value="Guncelle" icon="ui-icon-" update="updateDialog" oncomplete="updateDialog.show()"/>
<p:menuitem value="Sil" update="#form" icon="ui-icon-close" actionListener="#{functionControllerBean.deleteFunction}"/>
</p:contextMenu>
<p:dataTable resizableColumns="true" id="functions" var="function" value="#{functionControllerBean.functions}" rowKey="#{function.functionId}"
selection="#{functionControllerBean.selectedFunction}" selectionMode="single">
<p:column headerText="Id">
#{function.functionId}
</p:column>
<p:column headerText="Key ">
#{function.functionKey}
</p:column>
<p:column headerText="Isim" >
#{function.functionName}
</p:column>
<p:column headerText="Tip" >
#{function.functionType}
</p:column>
<p:column headerText="Url" >
#{function.uri}
</p:column>
<p:column headerText="Olusturulma Tarihi" >
#{function.creationDate}
</p:column>
<p:column headerText="Guncelleme Tarihi" >
#{function.lastUpdateDate}
</p:column>
<p:column headerText="Olusturan Kisi" >
#{function.createdBy}
</p:column>
<p:column headerText="Guncelleyen Kisi" >
#{function.createdBy}
</p:column>
</p:dataTable>
<p:dialog header="Islem Sonucu" widgetVar="actionResult" resizable="false"
width="200" showEffect="clip" hideEffect="fold" id="actionResult"
visible="#{functionControllerBean.actionResult!=null}">
<h:outputText value="#{functionControllerBean.actionResult}"/>
</p:dialog>
<p:dialog header="Guncelle" widgetVar="updateDialog" resizable="false"
width="200" showEffect="clip" hideEffect="fold" id="updateDialog" >
<h:panelGroup id="display">
<h:outputText value="#{functionControllerBean.selectedFunction.functionName}" />
<p:inputText value="#{functionControllerBean.selectedFunction.functionName}"/>
</h:panelGroup>
</p:dialog>
</h:form>