diff --git a/app/src/processing/app/Base.java b/app/src/processing/app/Base.java
index bc11927c0..f831ac13b 100644
--- a/app/src/processing/app/Base.java
+++ b/app/src/processing/app/Base.java
@@ -600,6 +600,10 @@ public class Base {
     item.addActionListener(e -> thinkDifferentExamples());
     defaultFileMenu.add(item);
 
+    item = new JMenuItem("Restart");
+    item.addActionListener(e -> handleRestart());
+    defaultFileMenu.add(item);
+
     return defaultFileMenu;
   }
 
@@ -858,16 +862,15 @@ public class Base {
     if (internalTools == null) {
       internalTools = new ArrayList<>();
 
-      initInternalTool("processing.app.tools.Archiver");
-      initInternalTool("processing.app.tools.ColorSelector");
-      initInternalTool("processing.app.tools.CreateFont");
+      initInternalTool(processing.app.tools.Archiver.class);
+      initInternalTool(processing.app.tools.ColorSelector.class);
+      initInternalTool(processing.app.tools.CreateFont.class);
 
       if (Platform.isMacOS()) {
-        initInternalTool("processing.app.tools.InstallCommander");
+        initInternalTool(processing.app.tools.InstallCommander.class);
       }
 
-      initInternalTool("processing.app.tools.ThemeSelector");
-      //initInternalTool("processing.app.tools.UpdateTheme");
+      initInternalTool(processing.app.tools.ThemeSelector.class);
     }
 
     // Only init() these the first time they're loaded
@@ -913,9 +916,8 @@ public class Base {
   }
 
 
-  protected void initInternalTool(String className) {
+  protected void initInternalTool(Class<?> toolClass) {
     try {
-      Class<?> toolClass = Class.forName(className);
       final Tool tool = (Tool)
         toolClass.getDeclaredConstructor().newInstance();
 
@@ -1681,18 +1683,6 @@ public class Base {
         }
       }
 
-      /*
-      // wow, this is wrong (should only be called after the last window)
-      // but also outdated, because it's instance_server.* not server.*
-      // and Preferences.save() is also about restoring sketches.
-
-      Preferences.unset("server.port"); //$NON-NLS-1$
-      Preferences.unset("server.key"); //$NON-NLS-1$
-
-      // Save out the current prefs state
-      Preferences.save();
-       */
-
       if (defaultFileMenu == null) {
         if (preventQuit) {
           // need to close this editor, ever so temporarily
@@ -1724,7 +1714,10 @@ public class Base {
 
 
   /**
-   * Handler for File &rarr; Quit.
+   * Handler for File &rarr; Quit. Note that this is *only* for the
+   * File menu. On macOS, it will not call System.exit() because the
+   * application will handle that. If calling this from elsewhere,
+   * you'll need a System.exit() call on macOS.
    * @return false if canceled, true otherwise.
    */
   public boolean handleQuit() {
@@ -1777,6 +1770,46 @@ public class Base {
   }
 
 
+  public void handleRestart() {
+    File app = Platform.getProcessingApp();
+    System.out.println(app);
+    if (app.exists()) {
+      if (handleQuitEach()) {  // only if everything saved
+        SingleInstance.clearRunning();
+
+        // Launch on quit
+        Runtime.getRuntime().addShutdownHook(new Thread(() -> {
+          try {
+            //Runtime.getRuntime().exec(app.getAbsolutePath());
+            System.out.println("launching");
+            Process p;
+            if (Platform.isMacOS()) {
+              p = Runtime.getRuntime().exec(new String[]{
+                "open", "-n", "-a", app.getAbsolutePath()
+              });
+            } else {
+              p = PApplet.launch(app.getAbsolutePath());
+            }
+            System.out.println("launched with result " + p.waitFor());
+            System.out.flush();
+          } catch (Exception e) {
+            e.printStackTrace();
+          }
+        }));
+        handleQuit();
+        // handleQuit() does not call System.exit() on macOS
+        if (Platform.isMacOS()) {
+          System.exit(0);
+        }
+      }
+    } else {
+      Messages.showWarning("Cannot Restart",
+        "Cannot automatically restart because the Processing\n" +
+        "application has been renamed. Please quit and then restart manually.");
+    }
+  }
+
+
   // . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
 
 
diff --git a/app/src/processing/app/Platform.java b/app/src/processing/app/Platform.java
index d6c73be9e..d6f472abe 100644
--- a/app/src/processing/app/Platform.java
+++ b/app/src/processing/app/Platform.java
@@ -3,7 +3,7 @@
 /*
   Part of the Processing project - http://processing.org
 
-  Copyright (c) 2012-20 The Processing Foundation
+  Copyright (c) 2012-23 The Processing Foundation
   Copyright (c) 2008-12 Ben Fry and Casey Reas
 
   This program is free software; you can redistribute it and/or modify
@@ -25,9 +25,12 @@ package processing.app;
 
 import java.io.File;
 import java.io.IOException;
+import java.lang.management.ManagementFactory;
 import java.net.URISyntaxException;
 import java.net.URL;
+import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import com.sun.jna.platform.FileUtils;
@@ -404,6 +407,114 @@ public class Platform {
   }
 
 
+  static protected File getProcessingApp() {
+    File appFile;
+    if (Platform.isMacOS()) {
+      // walks up from Processing.app/Contents/Java to Processing.app
+      // (or whatever the user has renamed it to)
+      appFile = getContentFile("../..");
+    } else if (Platform.isWindows()) {
+      appFile = getContentFile("processing.exe");
+    } else {
+      appFile = getContentFile("processing");
+    }
+    try {
+      return appFile.getCanonicalFile();
+
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+    return null;
+  }
+
+
+  // Not great, shows the crusty Duke icon in the dock.
+  // Better to just re-launch the .exe instead.
+  // Hacked up from <a href="https://lewisleo.blogspot.com/2012/08/programmatically-restart-java.html">this code</a>.
+  static private void restartJavaApplication() {
+    //    System.out.println("java path: " + javaPath);
+//    String java = System.getProperty("java.home") + "/bin/java";
+    // Tested and working with JDK 17 [fry 230122]
+//    System.out.println("sun java command: " + System.getProperty("sun.java.command"));
+//    System.out.println("class path: " + System.getProperty("java.class.path"));
+    List<String> cmd = new ArrayList<>();
+
+    // Add the path to the current java binary
+    cmd.add(getJavaPath());
+
+    // Get all the VM arguments that are currently in use
+    List<String> vmArguments =
+      ManagementFactory.getRuntimeMXBean().getInputArguments();
+
+    // Add all the arguments we're using now, except for -agentlib
+    for (String arg : vmArguments) {
+      if (!arg.contains("-agentlib")) {
+        cmd.add(arg);
+      }
+    }
+
+    // Does not work for .jar files, should this be used in a more general way
+    cmd.add("-cp");
+    cmd.add(System.getProperty("java.class.path"));
+
+    // Finally, add the class that was used to launch the app
+    // (in our case, this is the Processing splash screen)
+    String javaCommand = System.getProperty("sun.java.command");
+    String[] splitCommand = PApplet.split(javaCommand, ' ');
+//    if (splitCommand.length > 1) {
+//      try {
+//        Util.saveFile(javaCommand, PApplet.desktopFile("arrrrrghs.txt"));
+//      } catch (IOException e) {
+//        throw new RuntimeException(e);
+//      }
+//    }
+    cmd.add(splitCommand[0]);  // should be the main class name
+
+    ProcessBuilder builder = new ProcessBuilder(cmd);
+
+    /*
+    StringBuffer vmArgsOneLine = new StringBuffer();
+    for (String arg : vmArguments) {
+      // if it's the agent argument : we ignore it otherwise the
+      // address of the old application and the new one will be in conflict
+      if (!arg.contains("-agentlib")) {
+        vmArgsOneLine.append(arg);
+        vmArgsOneLine.append(" ");
+      }
+    }
+    // init the command to execute, add the vm args
+    final StringBuffer cmd = new StringBuffer("\"" + java + "\" " + vmArgsOneLine);
+    // program main and program arguments (be careful a sun property. might not be supported by all JVM)
+    String[] mainCommand = System.getProperty("sun.java.command").split(" ");
+    // program main is a jar
+    if (mainCommand[0].endsWith(".jar")) {
+      // if it's a jar, add -jar mainJar
+      cmd.append("-jar " + new File(mainCommand[0]).getPath());
+    } else {
+      // else it's a .class, add the classpath and mainClass
+      cmd.append("-cp \"" + System.getProperty("java.class.path") + "\" " + mainCommand[0]);
+    }
+    // finally add program arguments
+    for (int i = 1; i < mainCommand.length; i++) {
+      cmd.append(" ");
+      cmd.append(mainCommand[i]);
+    }
+    */
+    // execute the command in a shutdown hook, to be sure that all the
+    // resources have been disposed before restarting the application
+    Runtime.getRuntime().addShutdownHook(new Thread(() -> {
+      try {
+//        System.out.println(new StringList(cmd).join(" "));
+//        Runtime.getRuntime().exec(cmd.toArray(new String[0]));
+        builder.start();
+      } catch (IOException e) {
+        e.printStackTrace();
+      }
+    }));
+    System.exit(0);
+  }
+
+
   // . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
 
 
diff --git a/app/src/processing/app/SingleInstance.java b/app/src/processing/app/SingleInstance.java
index 405f6720c..f900d9e8f 100644
--- a/app/src/processing/app/SingleInstance.java
+++ b/app/src/processing/app/SingleInstance.java
@@ -54,6 +54,15 @@ public class SingleInstance {
   }
 
 
+  /**
+   * Disable briefly for Processing to restart itself.
+   */
+  static public void clearRunning() {
+    Preferences.unset(SERVER_PORT);
+    Preferences.save();
+  }
+
+
   static void startServer(final Base base) {
     try {
       Messages.log("Opening SingleInstance socket");
diff --git a/todo.txt b/todo.txt
index e214d19cf..6922f3e01 100755
--- a/todo.txt
+++ b/todo.txt
@@ -29,6 +29,11 @@ _ update console.scrollbar.thumb.rollover.color and console.scrollbar.thumb.pres
 _   currently just using .enabled.color because they weren't in ColorSet
 
 
+_ remove temporary 'restart' menu before release
+
+_ implement automatic updates?
+_   especially with fixes to updates on startup...
+
 _ export to IntelliJ? how tricky?
 _   just copy jars to /lib?
 _   point to binaries in /Applications/Processing.app? (no)