--- a/src/java.desktop/macosx/classes/sun/lwawt/macosx/CPlatformWindow.java	Wed Nov 01 10:43:44 2017 -0700
+++ b/src/java.desktop/macosx/classes/sun/lwawt/macosx/CPlatformWindow.java	Thu Nov 02 11:03:45 2017 -0700
@@ -47,6 +47,7 @@
 import java.lang.reflect.InvocationTargetException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Comparator;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.concurrent.atomic.AtomicReference;
@@ -238,6 +239,20 @@
             return (CPlatformWindow)((LWWindowPeer)acc.getPeer(root)).getPlatformWindow();
         }
     };
+    private final Comparator<Window> siblingsComparator = (w1, w2) -> {
+        if (w1 == w2) {
+            return 0;
+        }
+        ComponentAccessor componentAccessor = AWTAccessor.getComponentAccessor();
+        Object p1 = componentAccessor.getPeer(w1);
+        Object p2 = componentAccessor.getPeer(w2);
+        if (p1 instanceof LWWindowPeer && p2 instanceof LWWindowPeer) {
+            return Long.compare(
+                    ((CPlatformWindow) (((LWWindowPeer) p1).getPlatformWindow())).lastBecomeMainTime,
+                    ((CPlatformWindow) (((LWWindowPeer) p2).getPlatformWindow())).lastBecomeMainTime);
+        }
+        return 0;
+    };
 
     // Bounds of the native widget but in the Java coordinate system.
     // In order to keep it up-to-date we will update them on
@@ -259,6 +274,7 @@
     private boolean undecorated; // initialized in getInitialStyleBits()
     private Rectangle normalBounds = null; // not-null only for undecorated maximized windows
     private CPlatformResponder responder;
+    private long lastBecomeMainTime; // this is necessary to preserve right siblings order
 
     public CPlatformWindow() {
         super(0, true);
@@ -1186,8 +1202,9 @@
 
         final ComponentAccessor componentAccessor = AWTAccessor.getComponentAccessor();
         final WindowAccessor windowAccessor = AWTAccessor.getWindowAccessor();
-
+        Arrays.sort(windows, siblingsComparator);
         // Go through the list of windows and perform ordering.
+        CPlatformWindow pwUnder = null;
         for (Window w : windows) {
             boolean iconified = false;
             final Object p = componentAccessor.getPeer(w);
@@ -1201,11 +1218,15 @@
                     if (pw.isOneOfOwnersOrSelf(this)) {
                         pw.execute(CWrapper.NSWindow::orderFront);
                     } else {
-                        pw.owner.execute(ownerPtr -> {
+                        if (pwUnder == null) {
+                            pwUnder = pw.owner;
+                        }
+                        pwUnder.execute(underPtr -> {
                             pw.execute(ptr -> {
-                                CWrapper.NSWindow.orderWindow(ptr, CWrapper.NSWindow.NSWindowAbove, ownerPtr);
+                                CWrapper.NSWindow.orderWindow(ptr, CWrapper.NSWindow.NSWindowAbove, underPtr);
                             });
                         });
+                        pwUnder = pw;
                     }
                     pw.applyWindowLevel(w);
                 }
@@ -1242,6 +1263,7 @@
     }
 
     private void windowDidBecomeMain() {
+        lastBecomeMainTime = System.currentTimeMillis();
         if (checkBlockingAndOrder()) return;
         // If it's not blocked, make sure it's above its siblings
         orderAboveSiblings();

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/awt/Dialog/SiblingChildOrder/SiblingChildOrderTest.java	Thu Nov 02 11:03:45 2017 -0700
@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2017, 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 8190230
+ * @summary [macosx] Order of overlapping of modal dialogs is wrong
+ * @run main SiblingChildOrderTest
+ */
+
+import javax.swing.*;
+import java.awt.*;
+
+public class SiblingChildOrderTest
+
+{
+    static Color[] colors = new Color[]{Color.RED, Color.GREEN, Color.BLUE, Color.YELLOW};
+    static int[] x = new int[]{200, 150, 100, 50};
+    static int[] y = new int[]{200, 150, 100, 50};
+    static JDialog[] dlgs = new JDialog[4];
+    private static JFrame frame;
+
+    public static void main(String args[]) throws Exception {
+        SwingUtilities.invokeAndWait(() -> {
+            frame = new JFrame("FRAME");
+            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+            frame.setBounds(50, 50, 400, 400);
+            frame.setVisible(true);
+        });
+
+        for (int i = 0; i < colors.length; i++) {
+            int finalI = i;
+            SwingUtilities.invokeLater(() -> {
+                dlgs[finalI] = new JDialog(frame, "DLG " + finalI, true);
+                dlgs[finalI].getContentPane().setBackground(colors[finalI]);
+                dlgs[finalI].setBounds(x[finalI], y[finalI], 200, 200);
+                dlgs[finalI].setVisible(true);
+
+            });
+        }
+
+        Robot robot = new Robot();
+        robot.waitForIdle();
+        robot.delay(200);
+
+        for (int i = 0; i < colors.length; i++) {
+            Color c = robot.getPixelColor(x[i] + 190, y[i] + 190);
+            if (!c.equals(colors[i])) {
+                throw new RuntimeException("Expected " + colors[i] + " got " + c);
+            }
+        }
+
+        for (int i = 0; i < colors.length; i++) {
+            SwingUtilities.invokeLater(dlgs[i]::dispose);
+        }
+
+        SwingUtilities.invokeLater(frame::dispose);
+
+    }
+}