primefaces update fails on one page - jsf

Question

I'm sure that the question is asked before, but I can't fin my explicit problem, I'm afraid it is only a little typo and I can't see it.
I have a simple page in primefaces 10 with a toolbar, with an add-button, a table and a dialoge for adding the data. The dialog has a rendered tag that the requiered field are only rendered if there is a new variable. Everything I used on several other pages of my project.
The new Variable is initialized perfectly but the inside of the dialog isn't rendered, if I remove the rendered tag the field is rendered, but I have put some test-content into my new Variable and this isn't shown either, so I think that my update doesn't get called but I don't see why.
So here is my code:
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE composition PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<ui:composition xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:p="http://primefaces.org/ui"
template="layout.xhtml">
<ui:define name="header">
<div id="header">
ChangeLog
</div>
</ui:define>
<ui:define name="main">
<h:form id="changelogfrm">
<p:growl id="messages" showDetail="true" life="3000" />
<div class="card">
<p:toolbar>
<p:toolbarGroup>
<p:commandButton value="Neu" icon="pi pi-plus" actionListener="#{changeloghandler.newChangelog}"
update=":changelogfrm:manage-change-content" oncomplete="PF('manageChangeDialog').show()"
styleClass="ui-button-success" style="margin-right: .5rem" />
</p:toolbarGroup>
</p:toolbar>
<p:dataTable var="change" value="#{changeloghandler.changeLogs}"
showGridlines="true" size="small" id="dtChange">
<p:column headerText="Version">
<h:outputText value="#{change.version}" />
</p:column>
<p:column headerText="Typ">
<h:outputText value="#{change.changeType}"/>
</p:column>
<p:column headerText="Beschreibung">
<h:outputText value="#{change.description}"/>
</p:column>
<p:column headerText="Datum">
<h:outputText value="#{change.date}">
<f:convertDateTime type="date" pattern="dd.MM.yyyy HH:mm"/>
</h:outputText>
</p:column>
</p:dataTable>
<p:dialog header="Change" showEffect="fade" modal="true"
widgetVar="manageChangeDialog" responsive="true">
<p:outputPanel id="manage-change-content" class="ui-fluid">
<p:outputPanel rendered="#{not empty changeloghandler.selected}">
<div class="p-field">
<p:outputLabel for="chBeschreibung">Beschreibung</p:outputLabel>
<p:inputTextarea id="chBeschreibung" value="#{changeloghandler.selected.description}" required="true"/>
</div>
</p:outputPanel>
</p:outputPanel>
<f:facet name="footer">
<p:commandButton value="Save" icon="pi pi-check" actionListener="#{changeloghandler.save}"
update="manage-change-content" process="manage-change-content #this"/>
<p:commandButton value="Cancel" icon="pi pi-times" onclick="PF('manageChangeDialog').hide()"
class="ui-button-secondary"/>
</f:facet>
</p:dialog>
</div>
</h:form>
</ui:define>
</ui:composition>
The save-function in the dialog isn't called either.
I've also checked the html on the site, there is no double-form and the ids are set correctly.
Hope you can help me.
!!!EDIT!!!
Hi, here you have the Bean-Class:
package main.java.handler;
import java.io.Serializable;
import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.List;
import javax.annotation.PostConstruct;
import javax.enterprise.context.SessionScoped;
import javax.inject.Named;
import org.primefaces.PrimeFaces;
import main.java.persistence.entities.ChangeLog;
import main.java.persistence.entities.enums.ChangeType;
import main.java.persistence.entities.enums.Version;
import main.java.persistence.interfaces.ChangeLogDbInterface;
#Named("changeloghandler")
#SessionScoped
public class ChangeLogHandler implements Serializable{
private static final long serialVersionUID = 1L;
private List<ChangeLog> changeLogs;
private ChangeLog selected;
private List<Version> versions;
private ChangeType[] changeTypes;
#PostConstruct
private void init() {
changeLogs = ChangeLogDbInterface.loadChangeLogItems();
versions = new ArrayList<>();
for(Version v : Version.values()) {
if(v.isActive()) versions.add(v);
}
changeTypes = ChangeType.values();
}
public void newChangelog() {
ChangeLog newLog = new ChangeLog();
newLog.setDate(new Timestamp(System.currentTimeMillis()));
this.selected = newLog;
}
public void save() {
if (this.selected.getId() == 0) {
ChangeLogDbInterface.createChangeLogItem(selected);
this.changeLogs.add(this.selected);
}
else {
ChangeLogDbInterface.updateChangeLogItem(selected);
}
PrimeFaces.current().executeScript("PF('manageChangeDialog').hide()");
PrimeFaces.current().ajax().update("changelogfrm:dtChange");
}
public List<ChangeLog> getChangeLogs() { return changeLogs; }
public ChangeLog getSelected() { return selected; }
public List<Version> getVersions() { return versions; }
public ChangeType[] getChangeTypes() { return changeTypes; }
public void setChangeLogs(List<ChangeLog> changeLogs) { this.changeLogs = changeLogs; }
public void setSelected(ChangeLog selected) { this.selected = selected; }
public void setVersions(List<Version> versions) { this.versions = versions; }
public void setChangeTypes(ChangeType[] changeTypes) { this.changeTypes = changeTypes; }
}
!!! EDIT 2 !!!
Here is the template, but I think that doesn't help much either:
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:p="http://primefaces.org/ui"
xmlns:f="http://java.sun.com/jsf/core">
<h:head>
<title>Asset Tool Connector</title>
<link type="text/css"
href="${facesContext.externalContext.requestContextPath}/resources/css/style.css"
rel="stylesheet" />
<link type="image/x-icon"
href="${facesContext.externalContext.requestContextPath}/resources/images/netzwerk.png"
rel="shortcut icon" />
</h:head>
<h:body>
<ui:insert name="header"/>
<f:event listener="#{sessionHandler.checkLoggedIn}" type="preRenderView" />
<div id="menu">
<ui:include src="menu.xhtml" />
</div>
<div id="main">
<ui:insert name="main"/>
</div>
<div id="footer">
<div>
<h:form id="footerForm">
<p:commandButton value="ChangeLog" action="/changelog?faces-redirect=true"/>
</h:form>
</div>
© ATC - by 5332
</div>
</h:body>
</html>
Except the button in the footer links to the page with my issue, if that would be an issue.