src/macosx/classes/com/apple/laf/AquaPanelUI.java

*** 30,41 ****
--- 30,51 ----
  import javax.swing.plaf.basic.BasicPanelUI;
  
  import com.apple.laf.AquaUtils.RecyclableSingleton;
  import com.apple.laf.AquaUtils.RecyclableSingletonFromDefaultConstructor;
  
+ import java.awt.Graphics;
+ 
  public class AquaPanelUI extends BasicPanelUI {
      static RecyclableSingleton<AquaPanelUI> instance = new RecyclableSingletonFromDefaultConstructor<AquaPanelUI>(AquaPanelUI.class);
  
      public static ComponentUI createUI(final JComponent c) {
          return instance.get();
      }
+ 
+     @Override
+     public final void update(final Graphics g, final JComponent c) {
+         if (c.isOpaque()) {
+             AquaUtils.fillRect(g, c);
+         }
+         paint(g, c);
+     }
  }