FULL PRODUCT VERSION :
java version "1.8.0_92"
Java(TM) SE Runtime Environment (build 1.8.0_92-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.92-b14, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Linux dmovcc 3.19.0-32-generic #37~14.04.1-Ubuntu SMP Thu Oct 22 09:41:40 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

A DESCRIPTION OF THE PROBLEM :
After call "getRoot().getChildren().clear()", all tree item icons are still visible on the screen.

REGRESSION. Last worked in version 8u77

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Run the code snippet I attached to this bug report.
2. Click on "Clear all" button.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Only the root TreeItem must be visible.
ACTUAL -
The root TreeItem and icons of the old children are visible.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
package sample;

import javafx.application.Application;
import javafx.beans.property.SimpleStringProperty;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.control.cell.TextFieldTreeTableCell;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;

public class Main extends Application {

    @Override
    public void start(Stage primaryStage) throws Exception{
        final Image img1 = new Image("http://icons.iconarchive.com/icons/icons8/windows-8/24/Programming-Bug-icon.png", true);
        final Image img2 = new Image("http://icons.iconarchive.com/icons/iconsmind/outline/24/Bug-icon.png", true);

        final TreeTableView<String> treeTableView = new TreeTableView<>(new TreeItem<>("root", new ImageView(img1)));

        final TreeTableColumn<String, String> column1 = new TreeTableColumn<>("Col 1");
        column1.setPrefWidth(400);
        column1.setCellValueFactory(param -> new SimpleStringProperty(param.getValue().getValue()));
        column1.setCellFactory(TextFieldTreeTableCell.forTreeTableColumn());
        treeTableView.getColumns().add(column1);

        final TreeTableColumn<String, String> column2 = new TreeTableColumn<>("Col 2");
        column2.setPrefWidth(200);
        column2.setCellValueFactory(param -> new SimpleStringProperty(Integer.toString(param.getValue().getValue().length())));
        column2.setCellFactory(TextFieldTreeTableCell.forTreeTableColumn());
        treeTableView.getColumns().add(column2);

        treeTableView.setTreeColumn(column1);

        treeTableView.getRoot().getChildren().add(new TreeItem<>("child1", new ImageView(img1)));
        treeTableView.getRoot().getChildren().add(new TreeItem<>("child2", new ImageView(img2)));
        treeTableView.getRoot().getChildren().add(new TreeItem<>("child3", new ImageView(img1)));
        treeTableView.getRoot().getChildren().add(new TreeItem<>("child4", new ImageView(img2)));

        treeTableView.getRoot().setExpanded(true);

        final Button clearAllButton = new Button("Clear all");
        clearAllButton.setOnAction(event -> treeTableView.getRoot().getChildren().clear());
        final ToolBar toolBar = new ToolBar(clearAllButton);

        final BorderPane root = new BorderPane(treeTableView, toolBar, null, null, null);
        primaryStage.setTitle("TreeTableView bug");
        primaryStage.setScene(new Scene(root, 800, 600));
        primaryStage.show();
    }


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

---------- END SOURCE ----------