code: protected void paintScrollButtonBackground(SeaGlassContext ss, Graphics g, JButton scrollButton) {
          Rectangle tabRect = scrollButton.getBounds();
          int       x       = tabRect.x;
          int       y       = tabRect.y;
          int       height  = tabRect.height;
          int       width   = tabRect.width;
  
          boolean flipSegments = (orientation == ControlOrientation.HORIZONTAL && !tabPane.getComponentOrientation().isLeftToRight());
  
          SeaGlassLookAndFeel.updateSubregion(ss, g, tabRect);
  
          tabPane.putClientProperty("JTabbedPane.Tab.segmentPosition",
                                    ((scrollButton == scrollBackwardButton) ^ flipSegments) ? "first" : "last");
  
          int         oldState    = tabContext.getComponentState();
          ButtonModel model       = scrollButton.getModel();
          int         isPressed   = model.isPressed() && model.isArmed() ? PRESSED : 0;
          int         buttonState = SeaGlassLookAndFeel.getComponentState(scrollButton) | isPressed;
  
          tabContext.setComponentState(buttonState);
          tabContext.getPainter().paintTabbedPaneTabBackground(tabContext, g, x, y, width, height, -1, tabPlacement);
          tabContext.getPainter().paintTabbedPaneTabBorder(tabContext, g, x, y, width, height, -1, tabPlacement);
          tabContext.setComponentState(oldState);
      }
docs: Paint the background for a tab scroll button.
  
  @param ss           the tab subregion SynthContext.
  @param g            the Graphics context.
  @param scrollButton the button to paint.