diff -r 237dbcd482dc -r 66358a11c016 launcher/fx/src/main/java/org/apidesign/bck2brwsr/launcher/fximpl/JVMBridge.java
--- a/launcher/fx/src/main/java/org/apidesign/bck2brwsr/launcher/fximpl/JVMBridge.java	Thu Jan 09 11:55:01 2014 +0100
+++ b/launcher/fx/src/main/java/org/apidesign/bck2brwsr/launcher/fximpl/JVMBridge.java	Thu Jan 09 21:21:34 2014 +0100
@@ -81,7 +81,7 @@
     }
     
     private final class WebPresenter 
-    implements FindResources, Fn.Presenter, Fn.ToJavaScript, Executor {
+    implements FindResources, Fn.Presenter, Fn.ToJavaScript, Fn.FromJavaScript, Executor {
         @Override
         public void findResources(String name, Collection<? super URL> results, boolean oneIsEnough) {
             if (ldrs != null) for (ClassLoader l : ldrs) {
@@ -134,6 +134,11 @@
         }
 
         @Override
+        public Object toJava(Object js) {
+            return checkArray(js);
+        }
+
+        @Override
         public Object toJavaScript(Object toReturn) {
             if (toReturn instanceof Object[]) {
                 return convertArrays((Object[]) toReturn);