diff --git a/app/src/processing/app/ui/PreferencesFrame.java b/app/src/processing/app/ui/PreferencesFrame.java
index b2075ec93..f475f6bf3 100644
--- a/app/src/processing/app/ui/PreferencesFrame.java
+++ b/app/src/processing/app/ui/PreferencesFrame.java
@@ -65,7 +65,7 @@ public class PreferencesFrame {
 
   ColorChooser selector;
 
-//  JCheckBox errorCheckerBox;
+  JCheckBox errorCheckerBox;
   JCheckBox warningsCheckerBox;
   JCheckBox codeCompletionBox;
   JCheckBox importSuggestionsBox;
@@ -270,8 +270,11 @@ public class PreferencesFrame {
 
     // [ ] Continuously check for errors - PDE X
 
-//    errorCheckerBox =
-//      new JCheckBox(Language.text("preferences.continuously_check"));
+    errorCheckerBox =
+      new JCheckBox(Language.text("preferences.continuously_check"));
+    errorCheckerBox.addItemListener(e -> {
+      warningsCheckerBox.setEnabled(errorCheckerBox.isSelected());
+    });
 
 
     // [ ] Show Warnings - PDE X
@@ -407,9 +410,9 @@ public class PreferencesFrame {
                       .addComponent(presentColor, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE))
           .addComponent(editorAntialiasBox)
           .addComponent(inputMethodBox)
-//          .addGroup(layout.createSequentialGroup()
-//                      .addComponent(errorCheckerBox)
-//                      .addComponent(warningsCheckerBox))
+          .addGroup(layout.createSequentialGroup()
+                      .addComponent(errorCheckerBox)
+                      .addComponent(warningsCheckerBox))
           .addComponent(warningsCheckerBox)
           .addComponent(codeCompletionBox)
           .addComponent(importSuggestionsBox)
@@ -465,10 +468,9 @@ public class PreferencesFrame {
                   .addComponent(presentColor))
       .addComponent(editorAntialiasBox)
       .addComponent(inputMethodBox)
-//      .addGroup(layout.createParallelGroup()
-//                  .addComponent(errorCheckerBox)
-//                  .addComponent(warningsCheckerBox))
-      .addComponent(warningsCheckerBox)
+      .addGroup(layout.createParallelGroup()
+                  .addComponent(errorCheckerBox)
+                  .addComponent(warningsCheckerBox))
       .addComponent(codeCompletionBox)
       .addComponent(importSuggestionsBox)
       .addGroup(layout.createParallelGroup(GroupLayout.Alignment.CENTER)
@@ -655,7 +657,7 @@ public class PreferencesFrame {
                              autoAssociateBox.isSelected());
     }
 
-//    Preferences.setBoolean("pdex.errorCheckEnabled", errorCheckerBox.isSelected());
+    Preferences.setBoolean("pdex.errorCheckEnabled", errorCheckerBox.isSelected());
     Preferences.setBoolean("pdex.warningsEnabled", warningsCheckerBox.isSelected());
     Preferences.setBoolean("pdex.completion", codeCompletionBox.isSelected());
 //    Preferences.setBoolean("pdex.completion.trigger", codeCompletionTriggerBox.isSelected());
@@ -670,8 +672,9 @@ public class PreferencesFrame {
   public void showFrame() {
     editorAntialiasBox.setSelected(Preferences.getBoolean("editor.smooth")); //$NON-NLS-1$
     inputMethodBox.setSelected(Preferences.getBoolean("editor.input_method_support")); //$NON-NLS-1$
-//    errorCheckerBox.setSelected(Preferences.getBoolean("pdex.errorCheckEnabled"));
+    errorCheckerBox.setSelected(Preferences.getBoolean("pdex.errorCheckEnabled"));
     warningsCheckerBox.setSelected(Preferences.getBoolean("pdex.warningsEnabled"));
+    warningsCheckerBox.setEnabled(errorCheckerBox.isSelected());
     codeCompletionBox.setSelected(Preferences.getBoolean("pdex.completion"));
     //codeCompletionTriggerBox.setSelected(Preferences.getBoolean("pdex.completion.trigger"));
     //codeCompletionTriggerBox.setEnabled(codeCompletionBox.isSelected());
diff --git a/java/src/processing/mode/java/JavaMode.java b/java/src/processing/mode/java/JavaMode.java
index 7e3a07ef2..365fa3e6d 100644
--- a/java/src/processing/mode/java/JavaMode.java
+++ b/java/src/processing/mode/java/JavaMode.java
@@ -306,7 +306,7 @@ public class JavaMode extends Mode {
 //  }
 
 
-//  static public volatile boolean errorCheckEnabled = true;
+  static public volatile boolean errorCheckEnabled = true;
   static public volatile boolean warningsEnabled = true;
   static public volatile boolean codeCompletionsEnabled = true;
   static public volatile boolean debugOutputEnabled = false;
@@ -325,7 +325,7 @@ public class JavaMode extends Mode {
    */
   volatile public static int codeCompletionTriggerLength = 1;
 
-//  static public final String prefErrorCheck = "pdex.errorCheckEnabled";
+  static public final String prefErrorCheck = "pdex.errorCheckEnabled";
   static public final String prefWarnings = "pdex.warningsEnabled";
   static public final String prefDebugOP = "pdex.dbgOutput";
   static public final String prefErrorLogs = "pdex.writeErrorLogs";
@@ -351,7 +351,7 @@ public class JavaMode extends Mode {
   public void loadPreferences() {
     Messages.log("Load PDEX prefs");
     ensurePrefsExist();
-//    errorCheckEnabled = Preferences.getBoolean(prefErrorCheck);
+    errorCheckEnabled = Preferences.getBoolean(prefErrorCheck);
     warningsEnabled = Preferences.getBoolean(prefWarnings);
     codeCompletionsEnabled = Preferences.getBoolean(COMPLETION_PREF);
 //    DEBUG = Preferences.getBoolean(prefDebugOP);
@@ -370,7 +370,7 @@ public class JavaMode extends Mode {
 
   public void savePreferences() {
     Messages.log("Saving PDEX prefs");
-//    Preferences.setBoolean(prefErrorCheck, errorCheckEnabled);
+    Preferences.setBoolean(prefErrorCheck, errorCheckEnabled);
     Preferences.setBoolean(prefWarnings, warningsEnabled);
     Preferences.setBoolean(COMPLETION_PREF, codeCompletionsEnabled);
 //    Preferences.setBoolean(prefDebugOP, DEBUG);
@@ -429,8 +429,8 @@ public class JavaMode extends Mode {
 
   public void ensurePrefsExist() {
     //TODO: Need to do a better job of managing prefs. Think lists.
-//    if (Preferences.get(prefErrorCheck) == null)
-//      Preferences.setBoolean(prefErrorCheck, errorCheckEnabled);
+    if (Preferences.get(prefErrorCheck) == null)
+      Preferences.setBoolean(prefErrorCheck, errorCheckEnabled);
     if (Preferences.get(prefWarnings) == null)
       Preferences.setBoolean(prefWarnings, warningsEnabled);
     if (Preferences.get(COMPLETION_PREF) == null)
diff --git a/java/src/processing/mode/java/pdex/PDEX.java b/java/src/processing/mode/java/pdex/PDEX.java
index b30294ea7..b2ebd32c8 100644
--- a/java/src/processing/mode/java/pdex/PDEX.java
+++ b/java/src/processing/mode/java/pdex/PDEX.java
@@ -152,6 +152,7 @@ public class PDEX {
 
 
   public void preferencesChanged() {
+    errorChecker.preferencesChanged();
     sketchChanged();
   }
 
@@ -1026,16 +1027,22 @@ public class PDEX {
     private ScheduledExecutorService scheduler;
     private volatile ScheduledFuture<?> scheduledUiUpdate = null;
     private volatile long nextUiUpdate = 0;
+    private volatile boolean enabled = true;
 
     private final Consumer<PreprocessedSketch> errorHandlerListener = this::handleSketchProblems;
 
     private JavaEditor editor;
+    private PreprocessingService pps;
 
 
     public ErrorChecker(JavaEditor editor, PreprocessingService pps) {
       this.editor = editor;
+      this.pps = pps;
       scheduler = Executors.newSingleThreadScheduledExecutor();
-      pps.registerListener(errorHandlerListener);
+      this.enabled = JavaMode.errorCheckEnabled;
+      if (enabled) {
+        pps.registerListener(errorHandlerListener);
+      }
     }
 
 
@@ -1044,6 +1051,20 @@ public class PDEX {
     }
 
 
+    public void preferencesChanged() {
+      if (enabled != JavaMode.errorCheckEnabled) {
+        enabled = JavaMode.errorCheckEnabled;
+        if (enabled) {
+          pps.registerListener(errorHandlerListener);
+        } else {
+          pps.unregisterListener(errorHandlerListener);
+          editor.setProblemList(Collections.emptyList());
+          nextUiUpdate = 0;
+        }
+      }
+    }
+
+
     public void dispose() {
       if (scheduler != null) {
         scheduler.shutdownNow();