@Nullable
  @Override
  public Object getData(@NotNull @NonNls String dataId) {
    if (CommonDataKeys.PROJECT.is(dataId)) {
      return myProject;
    }
    else if (DiffDataKeys.PREV_NEXT_DIFFERENCE_ITERABLE.is(dataId)) {
      return myPrevNextDifferenceIterable;
    }
    return null;
  }
@Nullable
  @Override
  public Object getData(@NotNull @NonNls String dataId)