diff --git a/src/java/com/threerings/stage/data/StageScene.java b/src/java/com/threerings/stage/data/StageScene.java
index 899144977..c4ff4de5c 100644
--- a/src/java/com/threerings/stage/data/StageScene.java
+++ b/src/java/com/threerings/stage/data/StageScene.java
@@ -161,6 +161,12 @@ public class StageScene extends SceneImpl
         return _sdelegate.getPortals();
     }
 
+    // documentation inherited from interface
+    public short getNextPortalId ()
+    {
+        return _sdelegate.getNextPortalId();
+    }
+
     // documentation inherited from interface
     public Portal getDefaultEntrance ()
     {
diff --git a/src/java/com/threerings/stage/tools/editor/PortalTool.java b/src/java/com/threerings/stage/tools/editor/PortalTool.java
index 0757b6e3b..01a4537f1 100644
--- a/src/java/com/threerings/stage/tools/editor/PortalTool.java
+++ b/src/java/com/threerings/stage/tools/editor/PortalTool.java
@@ -119,6 +119,7 @@ public class PortalTool extends MouseInputAdapter
         _portal.name = name;
 
         // add the portal to the scene and pop up the editor dialog
+        _portal.portalId = _scene.getNextPortalId();
         _scene.addPortal(_portal);
         _panel.editPortal(_portal);
     }
diff --git a/src/java/com/threerings/whirled/spot/data/SpotScene.java b/src/java/com/threerings/whirled/spot/data/SpotScene.java
index 412fd5e34..54b60dbe1 100644
--- a/src/java/com/threerings/whirled/spot/data/SpotScene.java
+++ b/src/java/com/threerings/whirled/spot/data/SpotScene.java
@@ -1,5 +1,5 @@
 //
-// $Id: SpotScene.java,v 1.2 2004/08/27 02:20:46 mdb Exp $
+// $Id$
 //
 // Narya library - tools for developing networked games
 // Copyright (C) 2002-2004 Three Rings Design, Inc., All Rights Reserved
@@ -45,6 +45,12 @@ public interface SpotScene
      */
     public Iterator getPortals ();
 
+    /**
+     * Returns the portal id that should be assigned to the next portal
+     * added to this scene.
+     */
+    public short getNextPortalId ();
+
     /**
      * Returns the portal that represents the default entrance to this
      * scene. If a body enters the scene at logon time rather than
@@ -55,8 +61,9 @@ public interface SpotScene
 
     /**
      * Adds a portal to this scene, immediately making the requisite
-     * modifications to the underlying scene model. A portal id will be
-     * assigned to the portal by this method.
+     * modifications to the underlying scene model. The portal id should
+     * have already been assigned using the value obtained from {@link
+     * #getNextPortalId}.
      */
     public void addPortal (Portal portal);
 
diff --git a/src/java/com/threerings/whirled/spot/data/SpotSceneImpl.java b/src/java/com/threerings/whirled/spot/data/SpotSceneImpl.java
index b24787269..e26e77e21 100644
--- a/src/java/com/threerings/whirled/spot/data/SpotSceneImpl.java
+++ b/src/java/com/threerings/whirled/spot/data/SpotSceneImpl.java
@@ -1,5 +1,5 @@
 //
-// $Id: SpotSceneImpl.java,v 1.4 2004/08/27 02:20:46 mdb Exp $
+// $Id$
 //
 // Narya library - tools for developing networked games
 // Copyright (C) 2002-2004 Three Rings Design, Inc., All Rights Reserved
@@ -78,6 +78,18 @@ public class SpotSceneImpl
         return _portals.values().iterator();
     }
 
+    // documentation inherited from interface
+    public short getNextPortalId ()
+    {
+        // compute a new portal id for our friend the portal
+        for (short ii = 1; ii < MAX_PORTAL_ID; ii++) {
+            if (!_portals.containsKey(ii)) {
+                return ii;
+            }
+        }
+        return (short)-1;
+    }
+
     // documentation inherited from interface
     public Portal getDefaultEntrance ()
     {
@@ -87,21 +99,13 @@ public class SpotSceneImpl
     // documentation inherited from interface
     public void addPortal (Portal portal)
     {
-        // compute a new portal id for our friend the portal
-        portal.portalId = 0;
-        for (short ii = 1; ii < MAX_PORTAL_ID; ii++) {
-            if (!_portals.containsKey(ii)) {
-                portal.portalId = ii;
-                break;
-            }
-        }
-        if (portal.portalId == 0) {
-            Log.warning("Unable to assign id to new portal " +
-                        "[scene=" + this + "].");
+        if (portal.portalId <= 0) {
+            Log.warning("Refusing to add zero-id portal " +
+                        "[scene=" + this + ", portal=" + portal + "].");
             return;
         }
 
-        // add this beyotch to our model
+        // add it to our model
         _smodel.addPortal(portal);
 
         // and slap it into our table