src/macosx/classes/sun/lwawt/macosx/CPlatformWindow.java

@@ -858,12 +858,12 @@
         if (surfaceData instanceof CGLSurfaceData) {
             ((CGLSurfaceData)surfaceData).validate();
         }
     }
 
-    private void flushBuffers() {
-        if (isVisible() && !nativeBounds.isEmpty()) {
+    void flushBuffers() {
+        if (isVisible() && !nativeBounds.isEmpty() && !isFullScreenMode) {
             try {
                 LWCToolkit.invokeAndWait(new Runnable() {
                     @Override
                     public void run() {
                         //Posting an empty to flush the EventQueue without blocking the main thread