protected MergeThreesideViewer loadThreeSideViewer(@NotNull DiffContext context,
                                                     @NotNull ContentDiffRequest request,
                                                     @NotNull MergeContext mergeContext,
                                                     @NotNull TextMergeRequest mergeRequest,
                                                     @NotNull TextMergeViewer mergeViewer) {
    return new MergeThreesideViewer(context, request, mergeContext, mergeRequest, mergeViewer);
  }
protected MergeThreesideViewer loadThreeSideViewer(@NotNull DiffContext context,
                                                     @NotNull ContentDiffRequest request,
                                                     @NotNull MergeContext mergeContext,
                                                     @NotNull TextMergeRequest mergeRequest,
                                                     @NotNull TextMergeViewer mergeViewer)