@NotNull
    @Override
    protected String getText(@NotNull Side side) {
      return isBothEditable()
             ? DiffBundle.message("action.presentation.diff.append.to.the.side.text", myModifiedSide.getIndex())
             : DiffBundle.message("action.presentation.diff.append.text");
    }
@NotNull
    @Override
    protected String getText(@NotNull Side side)