private void AddNewIndexAndItem( int index, string levelName, Window window )
{
_indexList.Insert( index, levelName );
_windowToString.Add( window, levelName );
List<Window> list = new List<Window>();
list.Add( window );
_stringToWindows.Add( levelName, list );
window.Activated += window_Activated;
UpdateTopMostWindows();
}