--- a/src/java.desktop/macosx/native/libawt_lwawt/awt/AWTWindow.h	Thu Feb 21 11:10:35 2019 +0530
+++ b/src/java.desktop/macosx/native/libawt_lwawt/awt/AWTWindow.h	Thu Feb 21 12:27:39 2019 +0530
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011, 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
@@ -47,6 +47,7 @@
     jint preFullScreenLevel;
     NSRect standardFrame;
     BOOL isMinimizing;
+    BOOL keyNotificationRecd;
 }
 
 // An instance of either AWTWindow_Normal or AWTWindow_Panel
@@ -62,6 +63,7 @@
 @property (nonatomic) jint preFullScreenLevel;
 @property (nonatomic) NSRect standardFrame;
 @property (nonatomic) BOOL isMinimizing;
+@property (nonatomic) BOOL keyNotificationRecd;
 
 - (id) initWithPlatformWindow:(JNFWeakJObjectWrapper *)javaPlatformWindow
                   ownerWindow:owner

--- a/src/java.desktop/macosx/native/libawt_lwawt/awt/AWTWindow.m	Thu Feb 21 11:10:35 2019 +0530
+++ b/src/java.desktop/macosx/native/libawt_lwawt/awt/AWTWindow.m	Thu Feb 21 12:27:39 2019 +0530
@@ -186,6 +186,7 @@
 @synthesize preFullScreenLevel;
 @synthesize standardFrame;
 @synthesize isMinimizing;
+@synthesize keyNotificationRecd;
 
 - (void) updateMinMaxSize:(BOOL)resizable {
     if (resizable) {
@@ -319,6 +320,7 @@
     if (self.nsWindow == nil) return nil; // no hope either
     [self.nsWindow release]; // the property retains the object already
 
+    self.keyNotificationRecd = NO;
     self.isEnabled = YES;
     self.isMinimizing = NO;
     self.javaPlatformWindow = platformWindow;
@@ -747,9 +749,16 @@
 AWT_ASSERT_APPKIT_THREAD;
     [AWTToolkit eventCountPlusPlus];
 #ifdef DEBUG
-    NSLog(@"became main: %d %@ %@", [self.nsWindow isKeyWindow], [self.nsWindow title], [self menuBarForWindow]);
+    NSLog(@"became main: %d %@ %@ %d", [self.nsWindow isKeyWindow], [self.nsWindow title], [self menuBarForWindow], self.keyNotificationRecd);
 #endif
 
+    // if for some reason, no KEY notification is received but this main window is also a key window
+    // then we need to execute the KEY notification functionality.
+    if(self.keyNotificationRecd != YES && [self.nsWindow isKeyWindow]) {
+        [self doWindowDidBecomeKey];
+    }
+    self.keyNotificationRecd = NO;
+
     if (![self.nsWindow isKeyWindow]) {
         [self activateWindowMenuBar];
     }
@@ -769,6 +778,12 @@
 #ifdef DEBUG
     NSLog(@"became key: %d %@ %@", [self.nsWindow isMainWindow], [self.nsWindow title], [self menuBarForWindow]);
 #endif
+    [self doWindowDidBecomeKey];
+    self.keyNotificationRecd = YES;
+}
+
+- (void) doWindowDidBecomeKey {
+AWT_ASSERT_APPKIT_THREAD;
     AWTWindow *opposite = [AWTWindow lastKeyWindow];
 
     if (![self.nsWindow isMainWindow]) {