p:selectOneListbox ajax item selection changes scroll position - ajax

Question

There is a <p:selectOneListbox> with about 20 items. The first 5 items can be viewed in the list and then the remaining can be scrolled to and selected. The list is ajaxified. When the item numbers greater than 5 is selected (after scrolling to it) the scrollbar does not remain at its place; it moves to the top position. This makes the selected item (for example item 9) invisible. The program uses a ajax listener. The app uses PrimeFaces 5.0.
But, when the ajax listener is removed the selected (item 9) is visible and the scroller does not move to top (remove the p:ajax tag's listener attribute in the below JSF page).
I would like to know how to make the scrollbar not move when any item is selected while using the ajax listener.
The JSF page:
<p:selectOneListbox id="list"
scrollHeight="100"
value="#{bean.todo}">
<f:selectItems value="#{bean.data}"
var="t"
itemLabel="#{t.name}"
itemValue="#{t.name}"/>
<p:ajax process="#this"
update="#this msg"
listener="#{bean.valueChanged}" />
</p:selectOneListbox>
<br /><h:outputText id="msg" value="#{bean.message}" />
The bean's code:
import javax.faces.bean.*;
import java.io.Serializable;
import java.util.*;
import javax.faces.event.AjaxBehaviorEvent;
import javax.faces.component.UIOutput;
#ManagedBean(name="bean")
#SessionScoped
public class TodosBean implements Serializable {
private List<Todo> data;
private String todo; // selected item value
private String msg;
public TodosBean() {
loadData();
if (data.size() == 0) {
return;
}
Todo t = data.get(0);
String name = t.getName();
setTodo(name); // select the first item in the list
setMessage(name);
}
private void loadData() {
data = new ArrayList<>();
data.add(new Todo("1first", "1"));
data.add(new Todo("2second", "2"));
data.add(new Todo("3third", "3"));
data.add(new Todo("4fourth", "4"));
data.add(new Todo("5fifth", "5"));
data.add(new Todo("6sixth", "6"));
data.add(new Todo("7seventh", "7"));
data.add(new Todo("8eighth", "8"));
}
public List<Todo> getData() {
return data;
}
public void setMessage(String msg) {
this.msg = msg;
}
public String getMessage() {
return msg;
}
public String getTodo() {
return todo;
}
public void setTodo(String t) {
todo = t;
}
public void valueChanged(AjaxBehaviorEvent e) {
String name = (String) ((UIOutput) e.getSource()).getValue();
setMessage(name + " selected.");
}
}
public class Todo {
private String name;
private String desc;
public Todo() {}
public Todo(String name, String desc) {
this.name = name;
this.desc = desc;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDesc() {
return desc;
}
public void setDesc(String desc) {
this.desc = desc;
}
#Override
public String toString() {
return this.name;
}
}

Answer 1

Remove the update="#this will solve it. Updating a control will move it to a default state. It might also be that in a newer version of PF this default state is improved and it still is at the correct position