@Override
  public synchronized @NotNull VirtualFilePointerContainer createContainer(@NotNull Disposable parent, @Nullable VirtualFilePointerListener listener) {
    return registerContainer(parent, new VirtualFilePointerContainerImpl(this, parent, listener));
  }
@Override
  public synchronized @NotNull VirtualFilePointerContainer createContainer(@NotNull Disposable parent, @Nullable VirtualFilePointerListener listener)