diff --git a/core/todo.txt b/core/todo.txt
index a1507dcad..6867774be 100644
--- a/core/todo.txt
+++ b/core/todo.txt
@@ -14,6 +14,18 @@ X keyChar and keyCode are super wonky and unlike AWT
 X   https://github.com/processing/processing/issues/3290
 X   what's the way to do this after the deprecation?
 X   if this is going to be the default renderer, has to be ironed out
+X FX - arc - infamous deg-rad conversion strikes again
+X   https://github.com/processing/processing/pull/3713
+X FX - paths, contours, curves
+X   https://github.com/processing/processing/pull/3715
+X FX - fix AIOOBE when pressing ESC on Mac
+X   https://github.com/processing/processing/pull/3719
+X FX - framerate fix
+X   https://github.com/processing/processing/pull/3724
+X FX - loadPixels, updatePixels, get and set optimizations
+X   https://github.com/processing/processing/pull/3725
+X FX - keep track of whether pixels are up to date
+X   https://github.com/processing/processing/pull/3716
 
 
 known issues
diff --git a/java/src/processing/mode/java/JavaEditor.java b/java/src/processing/mode/java/JavaEditor.java
index 7619efea9..2a4242d4a 100644
--- a/java/src/processing/mode/java/JavaEditor.java
+++ b/java/src/processing/mode/java/JavaEditor.java
@@ -2514,6 +2514,16 @@ public class JavaEditor extends Editor {
   }
 
 
+  /*
+  public void clearErrorPoints() {
+    List<LineMarker> errorPoints = getErrorPoints();
+    synchronized (errorPoints) {  // necessary?
+      errorPoints.clear();
+    }
+  }
+  */
+
+
   public void repaintErrorBar() {
     errorColumn.repaint();
   }
diff --git a/java/src/processing/mode/java/pdex/ErrorCheckerService.java b/java/src/processing/mode/java/pdex/ErrorCheckerService.java
index 5d20c36f0..84d1dab1f 100644
--- a/java/src/processing/mode/java/pdex/ErrorCheckerService.java
+++ b/java/src/processing/mode/java/pdex/ErrorCheckerService.java
@@ -996,8 +996,9 @@ public class ErrorCheckerService implements Runnable {
     // editor.statusNotice("Position: " +
     // editor.getTextArea().getCaretLine());
     if (JavaMode.errorCheckEnabled) {
-      synchronized (editor.getErrorPoints()) {
-        for (LineMarker emarker : editor.getErrorPoints()) {
+      List<LineMarker> errorPoints = editor.getErrorPoints();
+      synchronized (errorPoints) {
+        for (LineMarker emarker : errorPoints) {
           if (emarker.getProblem().getLineNumber() == editor.getTextArea().getCaretLine()) {
             if (emarker.getType() == LineMarker.WARNING) {
               editor.statusMessage(emarker.getProblem().getMessage(),
@@ -1590,6 +1591,7 @@ public class ErrorCheckerService implements Runnable {
   public void handleErrorCheckingToggle() {
     if (!JavaMode.errorCheckEnabled) {
       Messages.log(editor.getSketch().getName() + " Error Checker paused.");
+      //editor.clearErrorPoints();
       editor.getErrorPoints().clear();
       problemsList.clear();
       updateErrorTable();
diff --git a/java/src/processing/mode/java/pdex/JavaTextAreaPainter.java b/java/src/processing/mode/java/pdex/JavaTextAreaPainter.java
index ebc614d58..42e0bcd00 100644
--- a/java/src/processing/mode/java/pdex/JavaTextAreaPainter.java
+++ b/java/src/processing/mode/java/pdex/JavaTextAreaPainter.java
@@ -345,15 +345,18 @@ public class JavaTextAreaPainter extends TextAreaPainter
     errorLineCoords.clear();
     // Check if current line contains an error. If it does, find if it's an
     // error or warning
-    for (LineMarker emarker : getJavaEditor().getErrorPoints()) {
-      if (emarker.getProblem().getLineNumber() == line) {
-        notFound = false;
-        if (emarker.getType() == LineMarker.WARNING) {
-          isWarning = true;
+    List<LineMarker> errorPoints = getJavaEditor().getErrorPoints();
+    synchronized (errorPoints) {
+      for (LineMarker emarker : errorPoints) {
+        if (emarker.getProblem().getLineNumber() == line) {
+          notFound = false;
+          if (emarker.getType() == LineMarker.WARNING) {
+            isWarning = true;
+          }
+          problem = emarker.getProblem();
+          //log(problem.toString());
+          break;
         }
-        problem = emarker.getProblem();
-        //log(problem.toString());
-        break;
       }
     }
 
diff --git a/todo.txt b/todo.txt
index 29a272881..eaa323df3 100644
--- a/todo.txt
+++ b/todo.txt
@@ -5,12 +5,18 @@ X   problem was that the example was creating files inside Processing.app
 X Casey reports that exported app still asks to download Java
 X   could this be a JOGL bug (linking against the app stub?)
 X   ran otool -L on the binaries and saw nothing
+X deal with ConcurrentModificationException in Editor 
+X   "Error repainting line range" and ConcurrentModificationException 
+X   https://github.com/processing/processing/issues/3726
 
 gsoc
 X CM: Category dropdown alignment
 X   https://github.com/processing/processing/issues/3644
 X   https://github.com/processing/processing/pull/3666
 X   https://github.com/processing/processing/pull/3669
+X finalize CM tab order
+X   https://github.com/processing/processing/issues/3613
+X   https://github.com/processing/processing/pull/3714
 
 fixed in b5, but unconfirmed at press time
 X CM - Focus is shifted out of the filter field when something is searched