@Nullable
    @Override
    public DiffTool getReplacement(@NotNull DiffTool tool, @NotNull DiffContext context, @NotNull DiffRequest request) {
      if (tool != myReplacement) return null;
      if (!canShow(context, request)) return null;
      return this;
    }
@Nullable
    @Override
    public DiffTool getReplacement(@NotNull DiffTool tool, @NotNull DiffContext context, @NotNull DiffRequest request)