Fix simulator skin scrollbar repaint

Ports/JavaSE/src/com/codename1/impl/javase/JavaSEPort.java

@@ -3676,6 +3676,10 @@ public void adjustmentValueChanged(AdjustmentEvent e) {
                 }
             }
             repaint();
+            Form current = JavaSEPort.this.getCurrentForm();
+            if (current != null) {
+                current.repaint();
+            }
 
         }
 

maven/javase/src/test/java/com/codename1/impl/javase/JavaSEPortSkinScrollbarTest.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2026, Codename One 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.  Codename One 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 Codename One through http://www.codenameone.com/ if
+ * you need additional information or have any questions.
+ */
+package com.codename1.impl.javase;
+
+import com.codename1.testing.junit.CodenameOneTest;
+import com.codename1.ui.Form;
+
+import org.junit.jupiter.api.Test;
+
+import java.awt.Adjustable;
+import java.awt.event.AdjustmentEvent;
+
+import javax.swing.JScrollBar;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+@CodenameOneTest
+public class JavaSEPortSkinScrollbarTest {
+
+    @Test
+    public void simulatorScrollbarAdjustmentRequestsCodenameOneRepaint() {
+        JavaSEPort port = JavaSEPort.instance;
+        RepaintCountingForm form = new RepaintCountingForm();
+        port.setCurrentForm(form);
+        form.repaintCount = 0;
+
+        port.canvas.setSize(200, 200);
+        JScrollBar scrollbar = new JScrollBar(Adjustable.VERTICAL);
+        scrollbar.setValues(50, 1, 0, 100);
+
+        port.canvas.adjustmentValueChanged(new AdjustmentEvent(scrollbar,
+                AdjustmentEvent.ADJUSTMENT_VALUE_CHANGED,
+                AdjustmentEvent.TRACK,
+                scrollbar.getValue()));
+
+        assertTrue(form.repaintCount > 0,
+                "Changing the simulator scrollbar offset must request a CN1 repaint; "
+                        + "otherwise Swing can redraw a stale buffer at a new offset and "
+                        + "subsequent clicks are routed against a different component tree "
+                        + "than the pixels visible on screen.");
+    }
+
+    private static class RepaintCountingForm extends Form {
+        int repaintCount;
+
+        @Override
+        public void repaint() {
+            repaintCount++;
+            super.repaint();
+        }
+    }
+}