public static void OpenArena()
{
logger.Trace("Open arena");
if (IsWindowOpen <Arena>())
{
_arena.Close();
}
_arena = new Arena(Client.ArenaAdmin);
Application.Current.Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Normal, new Action(() => _arena.Show()));
Application.Current.Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Normal, new Action(() => _arena.Activate()));
}