CTabFolder: support circular page traversal in MRU mode without chevron

bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/CTabFolder.java

@@ -2057,6 +2057,8 @@ void onPageTraversal(Event event) {
 					if (e.doit && !isDisposed()) {
 						showList(chevronRect);
 					}
+				} else {
+					index = visible [(current + offset + idx) % idx];
 				}
 			}
 		}

examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet395.java

@@ -0,0 +1,66 @@
+/*******************************************************************************
+ * Copyright (c) 2026 Contributors to the Eclipse Foundation
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *******************************************************************************/
+package org.eclipse.swt.snippets;
+
+/*
+ * CTabFolder example: circular keyboard page traversal.
+ *
+ * Give the CTabFolder focus and press Ctrl+PageDown / Ctrl+PageUp to move
+ * between tabs. With setMRUVisible(true) and no chevron shown (all tabs fit),
+ * navigating past the last tab now wraps around to the first tab, and
+ * navigating before the first tab wraps around to the last tab.
+ *
+ * For a list of all SWT example snippets see
+ * http://www.eclipse.org/swt/snippets/
+ */
+import org.eclipse.swt.*;
+import org.eclipse.swt.custom.*;
+import org.eclipse.swt.layout.*;
+import org.eclipse.swt.widgets.*;
+
+public class Snippet395 {
+	public static void main(String[] args) {
+		Display display = new Display();
+		Shell shell = new Shell(display);
+		shell.setLayout(new GridLayout());
+		shell.setText("Snippet 395");
+
+		Label label = new Label(shell, SWT.WRAP);
+		label.setText("Give the CTabFolder focus and press Ctrl+PageDown / Ctrl+PageUp.\n"
+				+ "Navigation now wraps around: last tab + PageDown -> first tab,\n"
+				+ "first tab + PageUp -> last tab.");
+		label.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false));
+
+		CTabFolder folder = new CTabFolder(shell, SWT.BORDER);
+		folder.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
+		// Enable most-recently-used tab ordering; all tabs below fit without a
+		// chevron, which is the case this fix addresses.
+		folder.setMRUVisible(true);
+
+		for (int i = 0; i < 4; i++) {
+			CTabItem item = new CTabItem(folder, SWT.NONE);
+			item.setText("Tab " + i);
+			Text text = new Text(folder, SWT.MULTI);
+			text.setText("Content for Tab " + i);
+			item.setControl(text);
+		}
+		folder.setSelection(0);
+
+		shell.setSize(400, 200);
+		shell.open();
+		while (!shell.isDisposed()) {
+			if (!display.readAndDispatch()) {
+				display.sleep();
+			}
+		}
+		display.dispose();
+	}
+}