After removing an item the previous one is selected. To reproduce:
- select "Item 2";
- press "Remove selected" button
"Item 2" will be removed. "Item 1" will be selected unexpectedly.

Sample to check:
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TreeItem;
import javafx.scene.control.TreeView;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class App extends Application {

    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage stage) {
        VBox content = new VBox();
        final TreeView tree_view = new TreeView();
        TreeItem<String> tree_model = new TreeItem<String>("Root");
        for (int i = 0; i < 5; i++) {
            TreeItem node = new TreeItem("Item " + i);
            tree_model.getChildren().add(node);
        }
        tree_view.setRoot(tree_model);
        tree_view.setShowRoot(true);
        tree_model.setExpanded(true);
        Button btn = new Button("Remove selected");
        btn.setOnAction(new EventHandler<ActionEvent>() {
            public void handle(ActionEvent t) {
                tree_view.getRoot().getChildren().removeAll(tree_view.getSelectionModel().getSelectedItems());
            }
        });
        content.getChildren().add(tree_view);
        content.getChildren().add(btn);
        stage.setScene(new Scene(content, 200, 200));
        stage.show();
    }
}