@RequiresWriteLock
  public void appendChange(@NotNull SimpleDiffChange change, @NotNull final Side sourceSide) {
    if (!change.isValid()) return;
    if (change.getStartLine(sourceSide) == change.getEndLine(sourceSide)) return;
    Side outputSide = sourceSide.other();

    DiffUtil.applyModification(getEditor(outputSide).getDocument(), change.getEndLine(outputSide), change.getEndLine(outputSide),
                               getEditor(sourceSide).getDocument(), change.getStartLine(sourceSide), change.getEndLine(sourceSide));

    myModel.destroyChange(change);
  }
@RequiresWriteLock
  public void appendChange(@NotNull SimpleDiffChange change, @NotNull final Side sourceSide)