p:commandButton is reloading the page to open dialog - jsf

Question

So I have this code:
<h:form id="serviceCustomFormForm">
<p:dialog id="parameterGroupAddDialog" widgetVar="parameterGroupAddDialog" header="#{messages.addParameterGroup}" modal="true" resizable="false">
<p:inputText value="#{serviceCustomFormBean.serviceParameterGroup.name}" styleClass="Wid90" />
<br />
<br />
<p:commandButton value="#{messages.save}" styleClass="Fright BlueButton" update="serviceCustomFormForm" actionListener="#{serviceCustomFormBean.addServiceParameterGroup}" oncomplete="PF('parameterGroupAddDialog').hide()" />
<p:commandButton value="#{messages.cancel}" styleClass="Fright RedButton" oncomplete="PF('parameterGroupAddDialog').hide()"/>
</p:dialog>
<div class="Container100">
<div class="ContainerIndent">
<p:commandButton value="#{messages.addParameterGroup}" icon="fa fa-plus-circle" styleClass="Fright CyanButton FloatNoneOnMobile" oncomplete="PF('parameterGroupAddDialog').show()" />
<div class="EmptyBox10 ShowOnMobile"></div>
</div>
</div>
</h:form>
When the page is first loaded the #PostConstruct method is called.
When I click the commandButton to open the dialog it's called again. And when I press the Cancel button inside the dialog it's called again.
This behavior does not occur in other parts of the application, and I can't see what I am missing here.
Update: As requested, the Bean code is here:
#ManagedBean
#ViewScoped
public final class ServiceCustomFormBean implements Serializable {
private ServiceParameterGroup serviceParameterGroup = new ServiceParameterGroup();
// Other attributes
#PostConstruct
private void init() {
// Reads attributes sent from previous page
}
public void addServiceParameterGroup() {
// Saves the serviceParameterGroup to database
}
// Getters and Setters
}

Answer 1

It's because the Commandbutton submits the form. You can
change to this:
<p:commandButton type="button" ...onclick="PF('parameterGroupAddDialog').hide()"
Type button tells primefaces not to submit the form. If the form isn't submitted oncomplete is never called. So it's onclick.

Answer 2

Try setting the following attributes to your 'Add Service' and 'Cancel' commandButton elements: partialSubmit="true" process="#this".
Code like this:
<commandButton value="#{messages.addParameterGroup}" ... partialSubmit="true" process="#this" ... />
By default, pf commandButtons try to submit the whole form, while in those two cases you just want to call the invoked method without doing a submit. With this, you are saying to primefaces that you don't want to submit it all (partialSubmit=true), and that you just want to process the invocation of the button itself (process=#this). Maybe that is your problem.
As an additional comment, i don't think getting the label values for the buttons from the bean is a good idea (unless you want to intentionally change the labels dynamically), because you will end up doing excessive requests to the bean. Better try using a messages properties file, as described in here http://www.mkyong.com/jsf2/jsf-2-0-and-resource-bundles-example/.

Answer 3

If I remember correctly, you should put your Dialog outside your main form, at the end of your body or use the appendTo="#(body)" param, and then, have another form inside the dialog.

Answer 4

After a long time dealing with this problem, I finally found the reason.
The annotation ViewScoped that I was importing in the backing bean was from the package javax.faces.view.
The correct one is javax.faces.bean.
Thanks for everyone that spend some time trying to help.