--- old/src/java.desktop/macosx/classes/com/apple/laf/AquaOptionPaneUI.java	2016-01-13 16:22:15.197465000 +0530
+++ new/src/java.desktop/macosx/classes/com/apple/laf/AquaOptionPaneUI.java	2016-01-13 16:22:15.021465000 +0530
@@ -141,5 +141,31 @@
                 xLocation += xOffset;
             }
         }
+
+        @Override
+        public Dimension minimumLayoutSize(Container c) {
+            if (c != null) {
+                Component[] children = c.getComponents();
+                if (children != null && children.length > 0) {
+                    int numChildren = children.length;
+                    Insets cInsets = c.getInsets();
+                    int extraHeight = cInsets.top + cInsets.bottom;
+                    int extraWidth = cInsets.left + cInsets.right;
+
+                    Dimension maxSize = new Dimension(kOKCancelButtonWidth,
+                            kButtonHeight);
+                    for (int i = 0; i < numChildren; i++) {
+                        Dimension sizes = children[i].getPreferredSize();
+                        maxSize.width = Math.max(maxSize.width, sizes.width);
+                        maxSize.height = Math.max(maxSize.height, sizes.height);
+                    }
+                    return new Dimension(extraWidth
+                            + (maxSize.width * numChildren)
+                            + (numChildren - 1) * padding,
+                            extraHeight + maxSize.height);
+                }
+            }
+            return new Dimension(0, 0);
+        }
     }
 }
--- /dev/null	2016-01-13 10:23:00.425465000 +0530
+++ new/test/javax/swing/JOptionPane/8139213/OptionPaneTest.java	2016-01-13 16:22:15.581465000 +0530
@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8139213
+ * @summary Mac OS Aqua X LAF: JOptionPane truncates the first button
+ * @run main OptionPaneTest
+ */
+import java.awt.Component;
+import java.awt.Insets;
+import java.awt.Robot;
+import javax.swing.JButton;
+import javax.swing.JDialog;
+import javax.swing.JOptionPane;
+import javax.swing.JPanel;
+import javax.swing.SwingUtilities;
+
+public class OptionPaneTest {
+
+    private volatile static boolean testFailed;
+    private static JDialog dialog;
+    private static Robot robot;
+
+    public static void main(final String[] args) throws Exception {
+        robot = new Robot();
+        SwingUtilities.invokeAndWait(new Runnable() {
+            @Override
+            public void run() {
+                try {
+                    JOptionPane optionPane = new JOptionPane("JOptionPane",
+                            JOptionPane.INFORMATION_MESSAGE,
+                            JOptionPane.DEFAULT_OPTION,
+                            null,
+                            new String[]{"3", "2", "1"},
+                            null);
+                    dialog = optionPane.createDialog("JOptionPane");
+                    int width = 0;
+                    Component[] comps = optionPane.getComponents();
+                    for (Component comp : comps) {
+                        if (comp instanceof JPanel) {
+                            Component[] child = ((JPanel) comp).getComponents();
+                            for (Component c : child) {
+                                if (c instanceof JButton) {
+                                    width += c.getWidth();
+                                }
+                            }
+                        }
+                    }
+                    Insets in = optionPane.getInsets();
+                    width += in.left + in.right;
+                    if (width > optionPane.getWidth()) {
+                        testFailed = true;
+                    }
+                } finally {
+                    dialog.dispose();
+                }
+            }
+        });
+        robot.waitForIdle();
+        if (testFailed) {
+            throw new RuntimeException("Test Failed");
+        }
+    }
+}