The only diffrence between ListBox is that this SimpleThemingListBox contains dependency properties to style ScrollViewer: background, border and thickness PointerOverItem, PointerOverPressed background etc.
Inheritance: Windows.UI.Xaml.Controls.ListBox
 /// <summary>
 /// Invoked whenever application code or internal processes (such as a rebuilding layout pass) call ApplyTemplate. In simplest terms, this means the method is called just before a UI element displays in your app. Override this method to influence the default post-template logic of a class.
 /// </summary>
 protected override void OnApplyTemplate()
 {
     this.UnsubscribeEvents();
     this.textBox = this.GetTemplateChild(TextBoxPropertyName) as UpDownTextBox;
     this.autoCompletePresenter            = this.GetTemplateChild(AutoCompletePresenterPropertyName) as Popup;
     this.autoCompletePresenter.Width      = this.ActualWidth;
     this.autocompleteItemsContainer       = this.GetTemplateChild(AutocompleteItemsContainerPropertyName) as SimpleThemingListBox;
     this.autocompleteItemsContainer.Width = this.ActualWidth;
     this.SetBorderThickness();
     base.OnApplyTemplate();
     this.SubscribeEvents();
 }
 /// <summary>
 /// Invoked whenever application code or internal processes (such as a rebuilding layout pass) call ApplyTemplate. In simplest terms, this means the method is called just before a UI element displays in your app. Override this method to influence the default post-template logic of a class.
 /// </summary>
 protected override void OnApplyTemplate()
 {
     this.UnsubscribeEvents();
     this.textBox = this.GetTemplateChild(TextBoxPropertyName) as UpDownTextBox;
     this.autoCompletePresenter = this.GetTemplateChild(AutoCompletePresenterPropertyName) as Popup;
     this.autoCompletePresenter.Width = this.ActualWidth;
     this.autocompleteItemsContainer = this.GetTemplateChild(AutocompleteItemsContainerPropertyName) as SimpleThemingListBox;
     this.autocompleteItemsContainer.Width = this.ActualWidth;
     this.SetBorderThickness();
     base.OnApplyTemplate();
     this.SubscribeEvents();
 }