diff --git a/src/dorkbox/util/swing/ActiveRenderLoop.java b/src/dorkbox/util/swing/ActiveRenderLoop.java
index afca4ea..e14d265 100644
--- a/src/dorkbox/util/swing/ActiveRenderLoop.java
+++ b/src/dorkbox/util/swing/ActiveRenderLoop.java
@@ -65,26 +65,28 @@ class ActiveRenderLoop implements Runnable {
                 actionHandlerLong.handle(updateDeltaNanos);
             }
 
-            for (int i = 0; i < SwingActiveRender.activeRenders.size(); i++) {
-                JFrame jFrame = SwingActiveRender.activeRenders.get(i);
+            // this needs to be synchronized because we don't want to our frame removed WHILE we are rendering it.
+            synchronized (SwingActiveRender.activeRenders) {
+                for (int i = 0; i < SwingActiveRender.activeRenders.size(); i++) {
+                    JFrame jFrame = SwingActiveRender.activeRenders.get(i);
 
-                final BufferStrategy buffer = jFrame.getBufferStrategy();
+                    final BufferStrategy buffer = jFrame.getBufferStrategy();
 
-                // maybe the frame was closed
-                if (buffer != null) {
-                    try {
-                        graphics = buffer.getDrawGraphics();
-                        jFrame.paint(graphics);
-                    } catch (IllegalStateException ignored) {
-                    } catch (Exception e) {
-                        e.printStackTrace();
-                    } finally {
-                        if (graphics != null) {
-                            graphics.dispose();
+                    // maybe the frame was closed
+                    if (buffer != null) {
+                        try {
+                            graphics = buffer.getDrawGraphics();
+                            jFrame.paint(graphics);
+                        } catch (Exception e) {
+                            e.printStackTrace();
+                        } finally {
+                            if (graphics != null) {
+                                graphics.dispose();
 
-                            // blit the back buffer to the screen
-                            if (!buffer.contentsLost()) {
-                                buffer.show();
+                                // blit the back buffer to the screen
+                                if (!buffer.contentsLost()) {
+                                    buffer.show();
+                                }
                             }
                         }
                     }
diff --git a/src/dorkbox/util/swing/SwingActiveRender.java b/src/dorkbox/util/swing/SwingActiveRender.java
index 9e0bf2c..a485410 100644
--- a/src/dorkbox/util/swing/SwingActiveRender.java
+++ b/src/dorkbox/util/swing/SwingActiveRender.java
@@ -18,6 +18,7 @@ package dorkbox.util.swing;
 import java.awt.Component;
 import java.awt.EventQueue;
 import java.util.ArrayDeque;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Deque;
 import java.util.List;
@@ -41,7 +42,7 @@ public final
 class SwingActiveRender {
     private static Thread activeRenderThread = null;
 
-    static final List<JFrame> activeRenders = new CopyOnWriteArrayList<JFrame>();
+    static final List<JFrame> activeRenders = new ArrayList<JFrame>();
     static final List<ActionHandlerLong> activeRenderEvents = new CopyOnWriteArrayList<ActionHandlerLong>();
 
     // volatile, so that access triggers thread synchrony, since 1.6. See the Java Language Spec, Chapter 17