popup disappear even when validation failed - jsf-2

Question

I am working with primefaces 3.5 and jsf2.I have a command Button that shows up a dialog as a popup to register a new customer. All fields are required. when i submit the form with missing some fields the popup disappears as if nothing happened. And when i click again on the button new it shows up the last filled form with error messages.
I need this to be shown first time i submit when validation is failed.
Here is a short version of my html code
<h:form id="mainForm">
<p:panel id="datatablePanel">
.........
<p:commandButton style="width: 8%;height: 100%" id="newButton" value="New" oncomplete="customerDialogNew.show()" icon="ui-icon-star"/>
</p:panel>
</:form>
<h:form id="newCustomerForm">
<p:panel id="customerPannel">
<p:dialog draggable="true" header="New Customer" widgetVar="customerDialogNew" id="dialog2">
<p:panelGrid id="newCustomer" columns="6" >
<p:outputLabel value="Name:" for="name" />
<p:inputText id="name" value="#{customerMB.name}" title="Name" required="true" requiredMessage="The Name field is required."/>
<p:message for="name" />
......
<p:commandButton style="height: 100%;width: 15%" value="Cancel" update="customerPannel" icon="ui-icon-arrowrefresh-1-n" process="#this" oncomplete="customerDialogNew.show()" />
<p:commandButton ajax="false" style="height: 100%;width: 15%" value="Save" icon="ui-icon-circle-check" styleClass="ui-priority-primary" actionListener="{customerMB.addCustomer()}"/>
</p:dialog>
</p:panel>
</h:form>

Answer 1

Cancel Button：
Change oncomplete="customerDialogNew.show()" to
oncomplete="customerDialogNew.hide()".
Save Button：
Remove ajax=false.
Add update="newCustomer".
So your Buttons looks like:
<p:commandButton style="height: 100%;width: 15%" value="Cancel" update="customerPannel" icon="ui-icon-arrowrefresh-1-n" process="#this" oncomplete="customerDialogNew.hide()" />
<p:commandButton style="height: 100%;width: 15%" value="Save" icon="ui-icon-circle-check" styleClass="ui-priority-primary" actionListener="#{customerMB.addCustomer()}" update="newCustomer"/>
Backing Bean：
public void addCustomer(){
//do something
System.out.println(name+"");
//set name to null to prevent seeing old value when adding the second(or more) customer
name=null;
//Hide customerDialogNew if everything done.
RequestContext.getCurrentInstance().execute("customerDialogNew.hide()");
}