src/java.desktop/share/classes/javax/swing/plaf/metal/MetalButtonUI.java

@@ -235,9 +235,9 @@
         }
         else {
             /*** paint the text disabled ***/
             g.setColor(getDisabledTextColor());
         }
-        SwingUtilities2.drawStringUnderlineCharAt(c, g,text,mnemIndex,
+        getTextUIDrawing().drawStringUnderlineCharAt(c, g,text,mnemIndex,
                                   textRect.x, textRect.y + fm.getAscent());
     }
 }