diff --git a/src/java/com/threerings/media/RegionManager.java b/src/java/com/threerings/media/RegionManager.java
index 6caed2b2f..01afb9128 100644
--- a/src/java/com/threerings/media/RegionManager.java
+++ b/src/java/com/threerings/media/RegionManager.java
@@ -1,5 +1,5 @@
 //
-// $Id: RegionManager.java,v 1.4 2002/10/17 02:11:58 ray Exp $
+// $Id: RegionManager.java,v 1.5 2002/10/29 20:33:26 shaper Exp $
 
 package com.threerings.media;
 
@@ -47,10 +47,16 @@ public class RegionManager
      */
     public void addDirtyRegion (Rectangle rect)
     {
-        if (rect.width != 0 && rect.height != 0) {
-//             Log.info("Invalidating " + StringUtil.toString(rect));
-            _dirty.add(rect);
+        // sanity-check the rectangle
+        if (rect == null || (rect.width <= 0 || rect.height <= 0)) {
+            Log.warning("Attempt to add invalid rectangle as a dirty region?!" +
+                        "[rect=" + StringUtil.toString(rect) + "].");
+            Thread.dumpStack();
+            return;
         }
+
+        // Log.info("Invalidating " + StringUtil.toString(rect));
+        _dirty.add(rect);
     }
 
     /**