--- a/src/java.desktop/windows/classes/com/sun/java/swing/plaf/windows/WindowsRootPaneUI.java	Fri Oct 19 12:39:56 2018 +0530
+++ b/src/java.desktop/windows/classes/com/sun/java/swing/plaf/windows/WindowsRootPaneUI.java	Fri Oct 19 12:50:25 2018 +0530
@@ -165,11 +165,13 @@
         }
 
         public boolean postProcessKeyEvent(KeyEvent ev) {
-            if(ev.isConsumed() && ev.getKeyCode() != KeyEvent.VK_ALT) {
-                // mnemonic combination, it's consumed, but we need
-                // set altKeyPressed to false, otherwise after selection
-                // component by mnemonic combination a menu will be open
-                altKeyPressed = false;
+            if (ev.isConsumed()) {
+                if (ev.getKeyCode() != KeyEvent.VK_ALT) {
+                    // mnemonic combination, it's consumed, but we need
+                    // set altKeyPressed to false, otherwise after selection
+                    // component by mnemonic combination a menu will be open
+                    altKeyPressed = false;
+                }
                 return false;
             }
             if (ev.getKeyCode() == KeyEvent.VK_ALT) {

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/com/sun/java/swing/plaf/windows/AltFocusIssueTest.java	Fri Oct 19 12:50:25 2018 +0530
@@ -0,0 +1,151 @@
+/*
+ * Copyright (c) 2018, 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 8211987
+   @requires (os.family == "windows")
+   @summary Verify if Menu bar gets input focus even if Alt-released event is consumed.
+   @modules java.desktop/com.sun.java.swing.plaf.windows
+   @run main AltFocusIssueTest
+*/
+
+import java.awt.event.KeyAdapter;
+import java.awt.event.KeyEvent;
+import java.lang.reflect.InvocationTargetException;
+import java.awt.Robot;
+import javax.swing.JFrame;
+import javax.swing.JMenu;
+import javax.swing.JMenuBar;
+import javax.swing.JMenuItem;
+import javax.swing.JTextArea;
+import javax.swing.SwingUtilities;
+import javax.swing.UIManager;
+import javax.swing.UnsupportedLookAndFeelException;
+
+/**
+ * Try to demonstrate the wrong behavior
+ */
+public class AltFocusIssueTest {
+
+    /**
+     * Menu inside menu bar of the frame
+     */
+    private static JMenu menu;
+
+    /**
+     * Text area to test on.
+     */
+    private static JTextArea ta;
+
+    private static JFrame frame;
+
+    /**
+     * Test that the text area loses input focus although Alt-released event is consumed.
+     *
+     * @throws InterruptedException
+     * @throws InvocationTargetException
+     */
+    public static void testAltEvents() throws Exception {
+        Robot robot = new Robot();
+        SwingUtilities.invokeAndWait(() -> {
+            try {
+                createUI();
+            } catch (Exception e) {
+                throw new RuntimeException(e);
+            }
+        });
+        robot.waitForIdle();
+        SwingUtilities.invokeAndWait(() -> ta.requestFocusInWindow());
+        robot.waitForIdle();
+        if (!ta.isFocusOwner()) {
+            throw new RuntimeException("textarea should have input focus");
+        }
+        if (menu.isSelected()) {
+            throw new RuntimeException("menu is selected...");
+        }
+
+        // Simulate an Alt-typed event
+        robot.keyPress(KeyEvent.VK_ALT);
+        robot.keyRelease(KeyEvent.VK_ALT);
+        robot.waitForIdle();
+
+        // Since the event is consumed, I expect the input focus to be in the text area
+        if (!ta.isFocusOwner()) {
+            throw new RuntimeException("textarea should still have input focus");
+        }
+        // OR
+        if (SwingUtilities.getRootPane(ta).isFocusOwner()) {
+            throw new RuntimeException("Focus should not be changed from the text area");
+        }
+        // OR
+        if (menu.isSelected()) {
+            throw new RuntimeException("Menu must not be selected");
+        }
+    }
+
+    /**
+     * Builds UI to test.
+     *
+     */
+    private static void createUI() throws Exception {
+        // Install Windows L&F
+        UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
+
+        frame = new JFrame();
+        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+
+        JMenuBar menuBar = new JMenuBar();
+        frame.setJMenuBar(menuBar);
+
+        menu = new JMenu("Menu");
+        menu.add(new JMenuItem("Menu item"));
+        menuBar.add(menu);
+
+        ta = new JTextArea();
+        frame.getContentPane().add(ta);
+
+        ta.addKeyListener( new KeyAdapter() {
+            @Override
+            public void keyReleased(KeyEvent e) {
+                if (e.getKeyCode() == KeyEvent.VK_ALT) {
+                    /*
+                     * This is where I need to do special handling of the Alt-released event.
+                     * After, nobody else must react to this event, thus I consume it.
+                     */
+                    e.consume();
+                }
+            }
+        });
+
+        frame.setSize(400, 300);
+        frame.setVisible(true);
+    }
+
+    public static void main(String[] args) throws Exception {
+        try {
+            testAltEvents();
+        } finally {
+            SwingUtilities.invokeAndWait(() -> frame.dispose());
+        }
+    }
+}