8351867: No UI changes while iconified

modules/javafx.graphics/src/main/java/com/sun/javafx/tk/quantum/GlassWindowEventHandler.java

@@ -58,10 +58,12 @@ public Void get() {
             case WindowEvent.MAXIMIZE:
                 stage.stageListener.changedIconified(false);
                 stage.stageListener.changedMaximized(true);
+                forceRepaint();
                 break;
             case WindowEvent.RESTORE:
                 stage.stageListener.changedIconified(false);
                 stage.stageListener.changedMaximized(false);
+                forceRepaint();
                 break;
             case WindowEvent.MOVE: {
                 float wx = window.getX();
@@ -105,15 +107,7 @@ public Void get() {
                 float outScaleX = window.getOutputScaleX();
                 float outScaleY = window.getOutputScaleY();
                 stage.stageListener.changedScale(outScaleX, outScaleY);
-                // We need to sync the new scales for painting
-                QuantumToolkit.runWithRenderLock(() -> {
-                    GlassScene scene = stage.getScene();
-                    if (scene != null) {
-                        scene.entireSceneNeedsRepaint();
-                        scene.updateSceneState();
-                    }
-                    return null;
-                });
+                forceRepaint();
                 break;
             }
             case WindowEvent.FOCUS_GAINED:
@@ -153,6 +147,20 @@ public Void get() {
         return null;
     }
 
+    /**
+     * Used to trigger a repaint after a window leaves an iconified state.
+     */
+    private void forceRepaint() {
+        QuantumToolkit.runWithRenderLock(() -> {
+            GlassScene scene = stage.getScene();
+            if (scene != null) {
+                scene.entireSceneNeedsRepaint();
+                scene.updateSceneState();
+            }
+            return null;
+        });
+    }
+
     @Override
     public void handleLevelEvent(int level) {
         QuantumToolkit.runWithoutRenderLock(() -> {

tests/system/src/test/java/test/robot/javafx/stage/DrawAfterDeiconifyTest.java

@@ -0,0 +1,125 @@
+/*
+ * Copyright (c) 2025, 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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.
+ */
+
+package test.robot.javafx.stage;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import javafx.application.Platform;
+import javafx.scene.Scene;
+import javafx.scene.layout.Pane;
+import javafx.scene.paint.Color;
+import javafx.stage.Stage;
+import javafx.stage.StageStyle;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Timeout;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.EnumSource;
+
+import static test.util.Util.TIMEOUT;
+
+import test.robot.testharness.VisualTestBase;
+
+/**
+ * Test that scene changes made while a stage is iconified get drawn after the
+ * stage is de-iconified.
+ *
+ * Note: on macOS you should run these tests with the Desktop & Dock
+ * "Minimize windows into application icon" setting turned off. When this
+ * setting is turned on the OS keeps generating new NSScreen objects and the
+ * resulting notifications will mask the original JavaFX bug.
+ */
+@Timeout(value=15000, unit=TimeUnit.MILLISECONDS)
+public class DrawAfterDeiconifyTest extends VisualTestBase {
+
+    private static final int WIDTH = 300;
+    private static final int HEIGHT = 300;
+
+    private static final Color FIRST_COLOR = Color.LIME;
+    private static final Color SECOND_COLOR = Color.HOTPINK;
+
+    private static final double TOLERANCE = 0.07;
+
+    private Stage stage;
+    private int centerX;
+    private int centerY;
+
+    public void redrawsAfterDeiconify(StageStyle stageStyle, final boolean maximized) throws Exception {
+        final CountDownLatch stageShownLatch = new CountDownLatch(1);
+
+        runAndWait(() -> {
+            stage = getStage(false);
+            stage.initStyle(stageStyle);
+            Scene scene = new Scene(new Pane(), WIDTH, HEIGHT);
+            scene.setFill(FIRST_COLOR);
+            stage.setScene(scene);
+            stage.setOnShown(e -> {
+                Platform.runLater(() -> {
+                    stage.setMaximized(maximized);
+                    centerX = (int)(stage.getX() + stage.getWidth() / 2.0);
+                    centerY = (int)(stage.getY() + stage.getHeight() / 2.0);
+                    stageShownLatch.countDown();
+                });
+            });
+            stage.show();
+        });
+
+        Assertions.assertTrue(stageShownLatch.await(TIMEOUT, TimeUnit.MILLISECONDS), "Timeout waiting for stage to be shown");
+
+        waitFirstFrame();
+        runAndWait(() -> {
+            Color color = getColor(centerX, centerY);
+            assertColorEquals(FIRST_COLOR, color, TOLERANCE);
+            stage.setIconified(true);
+        });
+
+        // Update the scene and then wait for a pulse to clear the pending
+        // paint request.
+        runAndWait(() -> stage.getScene().setFill(SECOND_COLOR));
+        waitNextFrame();
+
+        // Deiconify and verify that the scene change gets redrawn
+        runAndWait(() -> stage.setIconified(false));
+        waitNextFrame();
+        runAndWait(() -> {
+            Color color = getColor(centerX, centerY);
+            assertColorEquals(SECOND_COLOR, color, TOLERANCE);
+        });
+    }
+
+    @ParameterizedTest
+    @EnumSource(names = {"DECORATED", "UNDECORATED", "TRANSPARENT"})
+    public void stageRedrawsAfterDeiconify(StageStyle stageStyle) throws Exception {
+        redrawsAfterDeiconify(stageStyle, false);
+    }
+
+    @ParameterizedTest
+    @EnumSource(names = {"DECORATED", "UNDECORATED", "TRANSPARENT"})
+    public void maximizedStageRedrawsAfterDeiconify(StageStyle stageStyle) throws Exception {
+        redrawsAfterDeiconify(stageStyle, true);
+    }
+}