A DESCRIPTION OF THE PROBLEM :
States of selection and focus are cleared, when you set element to a ListView of size 1.
If ListView of size 2 or more, does not occur.
If initializing with FXCollections.observableArrayList, the error occurs in the second set somehow.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
execute the source code

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
States of selection and focus are not cleared.
ACTUAL -
runtime output of source code :
1-1 selectedIndex : 0, selectedItem : TEST1
1-1 focusedIndex : 0, focusedItem : TEST1
1-2 selectedIndex : -1, selectedItem : null
1-2 focusedIndex : -1, focusedItem : null
1-3 selectedIndex : -1, selectedItem : null
1-3 focusedIndex : -1, focusedItem : null

2-1 selectedIndex : 0, selectedItem : TEST1
2-1 focusedIndex : 0, focusedItem : TEST1
2-2 selectedIndex : 0, selectedItem : TEST2
2-2 focusedIndex : 0, focusedItem : TEST2
2-3 selectedIndex : 0, selectedItem : TEST3
2-3 focusedIndex : 0, focusedItem : TEST3

3-1 selectedIndex : 0, selectedItem : TEST1
3-1 focusedIndex : 0, focusedItem : TEST1
3-2 selectedIndex : 0, selectedItem : TEST2
3-2 focusedIndex : 0, focusedItem : TEST2
3-3 selectedIndex : -1, selectedItem : null
3-3 focusedIndex : -1, focusedItem : null

4-1 selectedIndex : 0, selectedItem : TEST1
4-1 focusedIndex : 0, focusedItem : TEST1
4-2 selectedIndex : 0, selectedItem : TEST2
4-2 focusedIndex : 0, focusedItem : TEST2
4-3 selectedIndex : 0, selectedItem : TEST3
4-3 focusedIndex : 0, focusedItem : TEST3

---------- BEGIN SOURCE ----------
import javafx.collections.FXCollections;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.ListView;

import java.net.URL;
import java.util.ResourceBundle;

public class Controller implements Initializable {
@FXML
private ListView<String> listView1;
@FXML
private ListView<String> listView2;
@FXML
private ListView<String> listView3;
@FXML
private ListView<String> listView4;

public void initialize(URL location, ResourceBundle resources) {
// ObservableList, size 1
listView1.getItems().add("TEST1");
listView1.getSelectionModel().select(0);
listView1.getFocusModel().focus(0);
printLog("1-1", listView1);
listView1.getItems().set(0, "TEST2");
printLog("1-2", listView1);
listView1.getItems().set(0, "TEST3");
printLog("1-3", listView1);
System.out.println();

// ObservableList, size 2
listView2.getItems().addAll("TEST1", "test1");
listView2.getSelectionModel().select(0);
listView2.getFocusModel().focus(0);
printLog("2-1", listView2);
listView2.getItems().set(0, "TEST2");
printLog("2-2", listView2);
listView2.getItems().set(0, "TEST3");
printLog("2-3", listView2);
System.out.println();

// observableArrayList, size 1
listView3.setItems(FXCollections.observableArrayList("TEST1"));
listView3.getSelectionModel().select(0);
listView3.getFocusModel().focus(0);
printLog("3-1", listView3);
listView3.getItems().set(0, "TEST2");
printLog("3-2", listView3);
listView3.getItems().set(0, "TEST3");
printLog("3-3", listView3);
System.out.println();

// observableArrayList, size 2
listView4.setItems(FXCollections.observableArrayList("TEST1", "test1"));
listView4.getSelectionModel().select(0);
listView4.getFocusModel().focus(0);
printLog("4-1", listView4);
listView4.getItems().set(0, "TEST2");
printLog("4-2", listView4);
listView4.getItems().set(0, "TEST3");
printLog("4-3", listView4);
System.out.println();
}

private void printLog(String label, ListView<String> listView) {
System.out.println(label + " selectedIndex : " + listView.getSelectionModel().getSelectedIndex() + ", selectedItem : " + listView.getSelectionModel().getSelectedItem());
System.out.println(label + " focusedIndex : " + listView.getFocusModel().getFocusedIndex() + ", focusedItem : " + listView.getFocusModel().getFocusedItem());
}
}
---------- END SOURCE ----------

FREQUENCY : always