listview - Strange behaviour of observable lists -

i bound observablelist listview perform tasks on listview. type of listview , observablelist model defined in model layer.so use cell factory render graphical node model objects. should add item observablelist user enter text in textfield. problem when user enter new text , add items observablelist additional unexpectec items apear @ listview. if add items observable list manualy out of event handler, list view works correctly. think because of threading issues cant solve it.

here simple example produce problem:

fxmldocumentcontroller.java:

public class fxmldocumentcontroller implements initializable { @fxml listview<string> list; observablelist<string> ol;  @fxml textfield text;  @override public void initialize(url url, resourcebundle rb) {     ol = fxcollections.observablearraylist();     list.setitems(ol);     list.setcellfactory((listview<string> param) -> {         listcell<string> lc = new listcell<string>(){             @override             protected void updateitem(string item, boolean empty){                 super.updateitem(item, empty);                 if(!empty){                     system.out.println("hi");                     parent root = null;                     try {                         root = fxmlloader.load(getclass().getresource("entry.fxml"));                     } catch (ioexception ex) {                     }                     ((label)(root.lookup("#label"))).settext(item);                     setgraphic(root);                 }             }         };         return lc;     });     text.setonaction((actionevent event) -> {         ol.add(text.gettext());         text.clear();     }); }     } 

fxmldoument.fxml:

<anchorpane id="anchorpane" prefheight="511.0" prefwidth="420.0" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/8" fx:controller="testapp.fxmldocumentcontroller"> <children>   <listview fx:id="list" layoutx="68.0" layouty="14.0" prefheight="391.0" prefwidth="284.0" />   <textfield fx:id="text" layoutx="110.0" layouty="419.0" /> </children> </anchorpane> 

entry.fxml:

<anchorpane id="anchorpane" prefheight="50.0" prefwidth="250.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1"> <children> <label fx:id="label" layoutx="70.0" layouty="18.0" prefheight="15.0" prefwidth="178.0" anchorpane.rightanchor="49.0" /> </children> </anchorpane> 

thanks in advances