public VerticalPanel buildUsersListPanel() {
    DockPanel headerDockPanel = new DockPanel();
    headerDockPanel.add(deleteUserBtn, DockPanel.EAST);
    VerticalPanel spacer = new VerticalPanel();
    spacer.setWidth("2"); // $NON-NLS-1$
    headerDockPanel.add(spacer, DockPanel.EAST);
    headerDockPanel.add(addUserBtn, DockPanel.EAST);
    Label label = new Label("Users"); // $NON-NLS-1$
    headerDockPanel.add(label, DockPanel.WEST);
    headerDockPanel.setCellWidth(label, "100%"); // $NON-NLS-1$
    VerticalPanel userListPanel = new VerticalPanel();
    userListPanel.add(headerDockPanel);
    userListPanel.add(usersList);
    userListPanel.add(new Label(Messages.getString("filter"))); // $NON-NLS-1$
    userListPanel.add(filterTextBox);

    userListPanel.setCellHeight(usersList, "100%"); // $NON-NLS-1$
    userListPanel.setCellWidth(usersList, "100%"); // $NON-NLS-1$
    userListPanel.setHeight("100%"); // $NON-NLS-1$
    userListPanel.setWidth("100%"); // $NON-NLS-1$
    usersList.setHeight("100%"); // $NON-NLS-1$
    usersList.setWidth("100%"); // $NON-NLS-1$
    filterTextBox.setWidth("100%"); // $NON-NLS-1$
    deleteUserBtn.setEnabled(false);

    filterTextBox.addKeyboardListener(this);
    usersList.addChangeListener(this);
    addUserBtn.addClickListener(this);
    deleteUserBtn.addClickListener(this);
    return userListPanel;
  }