@NotNull
  private MergeTool.MergeViewer createViewerFor(@NotNull MergeRequest request) {
    try {
      return getFittedTool(request).createComponent(myContext, request);
    }
    catch (Throwable e) {
      LOG.error(e);
      return ErrorMergeTool.INSTANCE.createComponent(myContext, request);
    }
  }
@NotNull
  private MergeTool.MergeViewer createViewerFor(@NotNull MergeRequest request)