@DirtyUI
  @Override
  public int getScrollableBlockIncrement(Rectangle visibleRect, int orientation, int direction) {
    if (orientation == SwingConstants.VERTICAL) {
      int lineHeight = editor.getLineHeight();
      if (direction > 0) {
        int lineNumber = (visibleRect.y + visibleRect.height) / lineHeight;
        return lineHeight * lineNumber - visibleRect.y;
      }
      else {
        int lineNumber = (visibleRect.y - visibleRect.height) / lineHeight;
        return visibleRect.y - lineHeight * lineNumber;
      }
    }
    // if orientation == SwingConstants.HORIZONTAL
    return visibleRect.width;
  }
@DirtyUI
  @Override
  public int getScrollableBlockIncrement(Rectangle visibleRect, int orientation, int direction)