Adding this line to the top of the run() method in

NativeEventThread seems to fix the hanging problem.

    this.setPriority(Thread.MIN_PRIORITY);


Looks like it was starvation.

java/webclient/classes_spec/org/mozilla/webclient/wrapper_native/NativeEventThread.java

@@ -172,6 +172,7 @@ public void delete()
 
 public void run() 
 {
+    this.setPriority(Thread.MIN_PRIORITY);
     Assert.assert(-1 != nativeWebShell);
     Assert.assert(null != windowControl);