Index: lib/OpenLayers/Layer/Vector.js
===================================================================
--- lib/OpenLayers/Layer/Vector.js	(revision 9721)
+++ lib/OpenLayers/Layer/Vector.js	(working copy)
@@ -651,7 +651,7 @@
         var all = (features == undefined); // evaluates to true if
                                            // features is null
         if(all) {
-            features = this.features;
+            features = this.features.slice();
         }
         if(features) {
             this.removeFeatures(features, options);