@Nullable
  private GutterIconRenderer createApplyRenderer() {
    return createIconRenderer(DiffBundle.message("action.presentation.diff.accept.text"), DiffUtil.getArrowIcon(Side.RIGHT),
                              () -> myViewer.executeCommand(DiffBundle.message("merge.dialog.accept.change.command"),
                                                            () -> myViewer.replaceChange(this)));
  }
@Nullable
  private GutterIconRenderer createApplyRenderer()