@RequiresEdt
  @Override
  public void onViewerCreated(@NotNull FrameDiffTool.DiffViewer viewer, @NotNull DiffContext context, @NotNull DiffRequest request) {
    if (request instanceof PreviewDiffRequest) {
      ((PreviewDiffRequest)request).setViewer(viewer);
    }
  }
@RequiresEdt
  @Override
  public void onViewerCreated(@NotNull FrameDiffTool.DiffViewer viewer, @NotNull DiffContext context, @NotNull DiffRequest request)