JBR-3706 Toggling full screen mode for two frames doesn't work on macOS if invoked without delay

(cherry picked from commit 28cfc4815f)
(cherry picked from commit ec4f29297e)

src/java.desktop/macosx/native/libawt_lwawt/awt/AWTWindow.m

@@ -1639,6 +1639,7 @@ JNI_COCOA_EXIT(env);
 }
 
 // undocumented approach which avoids focus stealing
+// and can be used full screen switch is in progress for another window
 void enableFullScreenSpecial(NSWindow *nsWindow) {
     NSKeyedArchiver *coder = [[NSKeyedArchiver alloc] init];
     [nsWindow encodeRestorableStateWithCoder:coder];
@@ -1667,12 +1668,17 @@ JNI_COCOA_ENTER(env);
     if (![nsWindow respondsToSelector:toggleFullScreenSelector]) return;
 
     [ThreadUtilities performOnMainThreadWaiting:NO block:^(){
-        if ((nsWindow.styleMask & NSWindowStyleMaskFullScreen) != NSWindowStyleMaskFullScreen && !NSApp.active) {
+        static BOOL inProgress = NO;
+        if ((nsWindow.styleMask & NSWindowStyleMaskFullScreen) != NSWindowStyleMaskFullScreen &&
+            (inProgress || !NSApp.active)) {
             enableFullScreenSpecial(nsWindow);
             if ((nsWindow.styleMask & NSWindowStyleMaskFullScreen) == NSWindowStyleMaskFullScreen) return; // success
             // otherwise fall back to standard approach
         }
+        BOOL savedValue = inProgress;
+        inProgress = YES;
         [nsWindow performSelector:toggleFullScreenSelector withObject:nil];
+        inProgress = savedValue;
     }];
 
 JNI_COCOA_EXIT(env);

test/jdk/jb/java/awt/Window/FullScreenTwoFrames.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright 2021 JetBrains s.r.o.
+ * 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.
+ */
+
+import com.apple.eawt.Application;
+import com.apple.eawt.FullScreenAdapter;
+import com.apple.eawt.FullScreenUtilities;
+import com.apple.eawt.event.FullScreenEvent;
+
+import javax.swing.*;
+import java.awt.event.WindowAdapter;
+import java.awt.event.WindowEvent;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * @test
+ * @summary Regression test for JBR-3706 Toggling full screen mode for two frames doesn't work on macOS
+ *          if invoked without delay
+ * @key headful
+ * @requires (os.family == "mac")
+ * @modules java.desktop/com.apple.eawt
+ *          java.desktop/com.apple.eawt.event
+ */
+
+public class FullScreenTwoFrames {
+    private static final CompletableFuture<Boolean> frame2Shown = new CompletableFuture<>();
+    private static final CompletableFuture<Boolean> frame1AtFullScreen = new CompletableFuture<>();
+    private static final CompletableFuture<Boolean> frame2AtFullScreen = new CompletableFuture<>();
+    private static JFrame frame1;
+    private static JFrame frame2;
+
+    public static void main(String[] args) throws Exception {
+        try {
+            SwingUtilities.invokeAndWait(FullScreenTwoFrames::initUI);
+            frame2Shown.get(5, TimeUnit.SECONDS);
+            Application.getApplication().requestToggleFullScreen(frame1);
+            Application.getApplication().requestToggleFullScreen(frame2);
+            frame1AtFullScreen.get(5, TimeUnit.SECONDS);
+            frame2AtFullScreen.get(5, TimeUnit.SECONDS);
+        }
+        finally {
+            SwingUtilities.invokeAndWait(FullScreenTwoFrames::disposeUI);
+        }
+    }
+
+    private static void initUI() {
+        frame1 = new JFrame("FullScreenTwoFrames(1)");
+        frame1.setBounds(100, 100, 200, 200);
+        FullScreenUtilities.addFullScreenListenerTo(frame1, new FullScreenAdapter() {
+            @Override
+            public void windowEnteredFullScreen(FullScreenEvent e) {
+                frame1AtFullScreen.complete(true);
+            }
+        });
+        frame1.setVisible(true);
+        frame2 = new JFrame("FullScreenTwoFrames(2)");
+        frame2.setBounds(100, 400, 200, 200);
+        frame2.addWindowListener(new WindowAdapter() {
+            @Override
+            public void windowOpened(WindowEvent e) {
+                frame2Shown.complete(true);
+            }
+        });
+        FullScreenUtilities.addFullScreenListenerTo(frame2, new FullScreenAdapter() {
+            @Override
+            public void windowEnteredFullScreen(FullScreenEvent e) {
+                frame2AtFullScreen.complete(true);
+            }
+        });
+        frame2.setVisible(true);
+    }
+
+    private static void disposeUI() {
+        if (frame1 != null) frame1.dispose();
+        if (frame2 != null) frame2.dispose();
+    }
+}