diff --git a/xwords4/android/XWords4/src/org/eehouse/android/xw4/XWActivity.java b/xwords4/android/XWords4/src/org/eehouse/android/xw4/XWActivity.java
index b7787cac1..488fa9858 100644
--- a/xwords4/android/XWords4/src/org/eehouse/android/xw4/XWActivity.java
+++ b/xwords4/android/XWords4/src/org/eehouse/android/xw4/XWActivity.java
@@ -26,6 +26,8 @@ import android.os.Bundle;
 import android.view.Menu;
 import android.view.MenuItem;
 
+import junit.framework.Assert;
+
 public class XWActivity extends Activity implements Delegator {
 
     private DelegateBase m_dlgt;
@@ -123,6 +125,7 @@ public class XWActivity extends Activity implements Delegator {
     protected Dialog onCreateDialog( int id )
     {
         Dialog dialog = super.onCreateDialog( id );
+        Assert.assertNull( dialog );
         if ( null == dialog ) {
             dialog = m_dlgt.onCreateDialog( id );
         }