To reproduce:

1. Select 3 items using SHIFT + Left Mouse Button; Three items will be selected.
2. Then make SHIFT + Left Mouse cilck on the first item
Expected: Only the first item is selected
Result: First and third items are selected

import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.scene.Scene;
import javafx.scene.control.ListView;
import javafx.scene.control.SelectionMode;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

public class ListViewSelection extends Application {

    public static final ObservableList names =
            FXCollections.observableArrayList();
    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage primaryStage) {
        primaryStage.setTitle("List View Sample");

        final ListView listView = new ListView(names);
        listView.getSelectionModel().setSelectionMode(SelectionMode.MULTIPLE);
        listView.setPrefSize(200, 250);
        names.addAll(
                "Adam", "Alex", "Alfred", "Albert",
                "Brenda", "Connie", "Derek", "Donny",
                "Lynne", "Myrtle", "Rose", "Rudolph",
                "Tony", "Trudy", "Williams", "Zach"

        );

        StackPane root = new StackPane();
        root.getChildren().add(listView);
        primaryStage.setScene(new Scene(root, 200, 250));
        primaryStage.show();
    }
}