Bloom.Edit.EditingModel.GetBookHasChanged C# (CSharp) Method

        public bool GetBookHasChanged()
        {
            return _currentlyDisplayedBook != CurrentBook;
        }

 /// <summary>
 /// this is called by our model, as a result of a "SelectedTabChangedEvent". So it's a lot more reliable than the normal winforms one.
 /// </summary>
 public void OnVisibleChanged(bool visible)
 {
     _visible = visible;
     if (visible)
     {
         if (_model.GetBookHasChanged())
         {
             //now we're doing it based on the focus textarea: ShowOrHideSourcePane(_model.ShowTranslationPanel);
             SetTranslationPanelVisibility();
             //even before showing, we need to clear some things so the user doesn't see the old stuff
             _pageListView.Clear();
             _templatePagesView.Clear();
         }
         Application.Idle += new EventHandler(VisibleNowAddSlowContents);
         Cursor            = Cursors.WaitCursor;
         Logger.WriteEvent("Entered Edit Tab");
     }
     else
     {
         Application.Idle -= new EventHandler(VisibleNowAddSlowContents); //make sure
         _browser1.Navigate("about:blank", false);                        //so we don't see the old one for moment, the next time we open this tab
     }
 }