PrimeFaces open dialog several times with rendered attribute - primefaces

Question

I try to implement a dialog box accessible everywhere in my project and I was wondering if this solution is possible.
The dialog is included in the template of my project. For example, where I am on the login page, I would like to show the dialog when the button "Login" is clicked and the authentication is successful. So I catch the bean linked to the dialog with:
getFacesContext().getELContext().getELResolver().getValue(getFacesContext().getELContext(), null, beanName);
and I set the "show" argument. (have a look below)
The first time, it's working. When I access the login page, the dialog is not rendered and when I click the button login, the attribute show is set, the page is updated and the dialog appears. But if I close it, I could not fire it again when I click again the button. (The dialog is rendered but not shown)
My dialog is like this (I have visible="true" cause I want to show each time it's rendered):
<h:form>
<p:dialog header="Dialog" widgetVar="myDialog" rendered="#{bean.show}" visible="true">
<p:ajax event="close" listener="#{bean.onClose}" />
...
</p:dialog>
</h:form>
The bean is in viewscope:
#ManagedBean(name = "bean")
#ViewScoped
public class MyBean {
private boolean show; // + Getters and Setters
#PostConstruct
public void init() {
this.show = false;
...
}
public void onClose() {
this.show = false;
}
}
And I can add that my LoginBean which is setting the show argument is in viewScope too.
Thanks