Add TriStateSwitchButton with two active states and off

widgets/opal/switchbutton/org.eclipse.nebula.widgets.opal.switchbutton.snippets/.classpath

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <classpath>
-	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-17"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-21"/>
 	<classpathentry kind="con" path="org.eclipse.pde.core.requiredPlugins"/>
 	<classpathentry kind="src" path="src"/>
 	<classpathentry kind="output" path="bin"/>

widgets/opal/switchbutton/org.eclipse.nebula.widgets.opal.switchbutton.snippets/.settings/org.eclipse.jdt.core.prefs

@@ -1,10 +1,10 @@
 eclipse.preferences.version=1
 org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
-org.eclipse.jdt.core.compiler.codegen.targetPlatform=17
-org.eclipse.jdt.core.compiler.compliance=17
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=21
+org.eclipse.jdt.core.compiler.compliance=21
 org.eclipse.jdt.core.compiler.problem.assertIdentifier=error
 org.eclipse.jdt.core.compiler.problem.enablePreviewFeatures=disabled
 org.eclipse.jdt.core.compiler.problem.enumIdentifier=error
 org.eclipse.jdt.core.compiler.problem.reportPreviewFeatures=warning
 org.eclipse.jdt.core.compiler.release=enabled
-org.eclipse.jdt.core.compiler.source=17
+org.eclipse.jdt.core.compiler.source=21

widgets/opal/switchbutton/org.eclipse.nebula.widgets.opal.switchbutton.snippets/META-INF/MANIFEST.MF

@@ -4,7 +4,7 @@ Bundle-Name: Nebula Opal Switch Button Snippets
 Bundle-SymbolicName: org.eclipse.nebula.widgets.opal.switchbutton.snippets
 Bundle-Version: 1.0.0.qualifier
 Bundle-Vendor: Eclipse Nebula
-Bundle-RequiredExecutionEnvironment: JavaSE-17
+Bundle-RequiredExecutionEnvironment: JavaSE-21
 Require-Bundle: org.eclipse.nebula.widgets.opal.switchbutton;bundle-version="1.0.0",
  org.eclipse.swt
 Automatic-Module-Name: org.eclipse.nebula.widgets.opal.switchbutton.snippets

widgets/opal/switchbutton/org.eclipse.nebula.widgets.opal.switchbutton.snippets/src/org/eclipse/nebula/widgets/opal/switchbutton/snippets/TriStateSwitchButtonSnippet.java

@@ -0,0 +1,192 @@
+/*******************************************************************************
+ * Copyright (c) 2026 Christoph Läubrich
+ *
+ * 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
+ *
+ * Contributors:
+ * Christoph Läubrich - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.nebula.widgets.opal.switchbutton.snippets;
+
+import org.eclipse.nebula.widgets.opal.switchbutton.TriState;
+import org.eclipse.nebula.widgets.opal.switchbutton.TriStateSwitchButton;
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.events.DisposeEvent;
+import org.eclipse.swt.events.DisposeListener;
+import org.eclipse.swt.events.SelectionEvent;
+import org.eclipse.swt.events.SelectionListener;
+import org.eclipse.swt.graphics.Font;
+import org.eclipse.swt.layout.GridLayout;
+import org.eclipse.swt.widgets.Display;
+import org.eclipse.swt.widgets.Event;
+import org.eclipse.swt.widgets.Listener;
+import org.eclipse.swt.widgets.Shell;
+
+/**
+ * A simple snippet for the TriStateSwitchButton widget.
+ *
+ * <p>
+ * Click behavior:
+ * <ul>
+ * <li>When FIRST or SECOND: any click → OFF</li>
+ * <li>When OFF: click left section → FIRST, click right section → SECOND, click
+ * center section → no change</li>
+ * </ul>
+ * </p>
+ */
+public class TriStateSwitchButtonSnippet {
+
+	public static void main(final String[] args) {
+		final Display display = new Display();
+		final Shell shell = new Shell(display);
+		shell.setText("TriStateSwitchButton Snippet");
+		shell.setSize(700, 700);
+		shell.setLayout(new GridLayout(1, false));
+
+		// Default – starts in OFF state
+		final TriStateSwitchButton button1 = new TriStateSwitchButton(shell, SWT.NONE);
+		button1.setText("Default (starts OFF)");
+
+		// Custom section labels
+		final TriStateSwitchButton button2 = new TriStateSwitchButton(shell, SWT.NONE);
+		button2.setTextForFirst("Left");
+		button2.setTextForOff("Neutral");
+		button2.setTextForSecond("Right");
+		button2.setText("Custom labels");
+
+		// Starts in FIRST state
+		final TriStateSwitchButton button3First = new TriStateSwitchButton(shell, SWT.NONE);
+		button3First.setState(TriState.FIRST);
+		button3First.setText("Starts in FIRST state");
+
+		// Starts in SECOND state
+		final TriStateSwitchButton button3Second = new TriStateSwitchButton(shell, SWT.NONE);
+		button3Second.setState(TriState.SECOND);
+		button3Second.setText("Starts in SECOND state");
+
+		// With a border
+		final TriStateSwitchButton button4 = new TriStateSwitchButton(shell, SWT.NONE);
+		button4.setBorderColor(display.getSystemColor(SWT.COLOR_DARK_RED));
+		button4.setText("With border");
+
+		// Disabled – all three starting states
+		final TriStateSwitchButton button5Off = new TriStateSwitchButton(shell, SWT.NONE);
+		button5Off.setEnabled(false);
+		button5Off.setText("Disabled (OFF)");
+
+		final TriStateSwitchButton button5First = new TriStateSwitchButton(shell, SWT.NONE);
+		button5First.setState(TriState.FIRST);
+		button5First.setEnabled(false);
+		button5First.setText("Disabled (FIRST)");
+
+		final TriStateSwitchButton button5Second = new TriStateSwitchButton(shell, SWT.NONE);
+		button5Second.setState(TriState.SECOND);
+		button5Second.setEnabled(false);
+		button5Second.setText("Disabled (SECOND)");
+
+		// Without glow / focus effect
+		final TriStateSwitchButton button6 = new TriStateSwitchButton(shell, SWT.NONE);
+		button6.setFocusColor(null);
+		button6.setText("No focus/hover effect");
+
+		// Square (non-rounded)
+		final TriStateSwitchButton button7 = new TriStateSwitchButton(shell, SWT.NONE);
+		button7.setRound(false);
+		button7.setText("Square style");
+
+		// Custom colors for all three sections
+		final TriStateSwitchButton button8 = new TriStateSwitchButton(shell, SWT.NONE);
+		button8.setFirstBackgroundColor(display.getSystemColor(SWT.COLOR_DARK_BLUE));
+		button8.setFirstForegroundColor(display.getSystemColor(SWT.COLOR_WHITE));
+		button8.setOffBackgroundColor(display.getSystemColor(SWT.COLOR_DARK_GRAY));
+		button8.setOffForegroundColor(display.getSystemColor(SWT.COLOR_WHITE));
+		button8.setSecondBackgroundColor(display.getSystemColor(SWT.COLOR_DARK_RED));
+		button8.setSecondForegroundColor(display.getSystemColor(SWT.COLOR_WHITE));
+		button8.setButtonBorderColor(display.getSystemColor(SWT.COLOR_BLACK));
+		button8.setText("Custom section colors");
+
+		// Selection listener – reports the new state
+		final TriStateSwitchButton button9 = new TriStateSwitchButton(shell, SWT.NONE);
+		button9.setText("Selection listener");
+		button9.addSelectionListener(new SelectionListener() {
+
+			@Override
+			public void widgetSelected(final SelectionEvent e) {
+				System.out.println("New state: " + button9.getState());
+			}
+
+			@Override
+			public void widgetDefaultSelected(final SelectionEvent e) {
+			}
+		});
+
+		// Selection listener with doit=false – cancels the state change
+		final TriStateSwitchButton button10 = new TriStateSwitchButton(shell, SWT.NONE);
+		button10.setText("Listener with doit=false (change blocked)");
+		button10.addSelectionListener(new SelectionListener() {
+
+			@Override
+			public void widgetSelected(final SelectionEvent e) {
+				System.out.println("Change vetoed – state stays: " + button10.getState());
+				e.doit = false;
+			}
+
+			@Override
+			public void widgetDefaultSelected(final SelectionEvent e) {
+			}
+		});
+
+		// Low-level SWT listener
+		final TriStateSwitchButton button11 = new TriStateSwitchButton(shell, SWT.NONE);
+		button11.setFocusColor(null);
+		button11.setText("Low-level SWT listener (beeps on change)");
+		button11.addListener(SWT.Selection, new Listener() {
+
+			@Override
+			public void handleEvent(final Event event) {
+				event.display.beep();
+			}
+		});
+
+		// Custom font
+		final TriStateSwitchButton button12 = new TriStateSwitchButton(shell, SWT.NONE);
+		final Font font = new Font(display, "Courier New", 16, SWT.BOLD | SWT.ITALIC);
+		shell.addDisposeListener(new DisposeListener() {
+
+			@Override
+			public void widgetDisposed(final DisposeEvent e) {
+				font.dispose();
+			}
+		});
+		button12.setFont(font);
+		button12.setText("Custom font");
+
+		// Custom margins and arc
+		final TriStateSwitchButton button13 = new TriStateSwitchButton(shell, SWT.NONE);
+		button13.setInsideMargin(10, 3);
+		button13.setArc(4);
+		button13.setText("Custom margins & arc");
+
+		// Widget background and foreground (label area)
+		final TriStateSwitchButton button14 = new TriStateSwitchButton(shell, SWT.NONE);
+		button14.setBackground(display.getSystemColor(SWT.COLOR_YELLOW));
+		button14.setForeground(display.getSystemColor(SWT.COLOR_DARK_RED));
+		button14.setText("Custom widget background/foreground");
+
+		shell.pack();
+		shell.open();
+
+		while (!shell.isDisposed()) {
+			if (!display.readAndDispatch()) {
+				display.sleep();
+			}
+		}
+		display.dispose();
+	}
+
+}

widgets/opal/switchbutton/org.eclipse.nebula.widgets.opal.switchbutton/src/org/eclipse/nebula/widgets/opal/switchbutton/TriState.java

@@ -0,0 +1,36 @@
+/*******************************************************************************
+ * Copyright (c) 2026 Christoph Läubrich
+ *
+ * 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
+ *
+ * Contributors:
+ * Christoph Läubrich - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.nebula.widgets.opal.switchbutton;
+
+/**
+ * Represents the three possible states of a {@link TriStateSwitchButton}.
+ *
+ * <ul>
+ * <li>{@link #FIRST} - the first active state, shown at the left position.</li>
+ * <li>{@link #OFF} - the neutral/off state, shown at the center position.</li>
+ * <li>{@link #SECOND} - the second active state, shown at the right position.</li>
+ * </ul>
+ */
+public enum TriState {
+
+	/** The first active state (left position). */
+	FIRST,
+
+	/** The neutral/off state (center position). */
+	OFF,
+
+	/** The second active state (right position). */
+	SECOND
+
+}