diff --git a/src/EditSession.java b/src/EditSession.java
index 39e28db9a..7e112417d 100644
--- a/src/EditSession.java
+++ b/src/EditSession.java
@@ -46,15 +46,15 @@ public class EditSession {
     /**
      * Stores the original blocks before modification.
      */
-    private Map<BlockVector,BaseBlock> original = new HashMap<BlockVector,BaseBlock>();
+    private DoubleArrayList<BlockVector,BaseBlock> original = new DoubleArrayList<BlockVector,BaseBlock>();
     /**
      * Stores the current blocks.
      */
-    private Map<BlockVector,BaseBlock> current = new HashMap<BlockVector,BaseBlock>();
+    private DoubleArrayList<BlockVector,BaseBlock> current = new DoubleArrayList<BlockVector,BaseBlock>();
     /**
      * Queue.
      */
-    private Map<BlockVector,BaseBlock> queue = new HashMap<BlockVector,BaseBlock>();
+    private DoubleArrayList<BlockVector,BaseBlock> queue = new DoubleArrayList<BlockVector,BaseBlock>();
     /**
      * The maximum number of blocks to change at a time. If this number is
      * exceeded, a MaxChangedBlocksException exception will be
@@ -149,13 +149,13 @@ public class EditSession {
         throws MaxChangedBlocksException {
         BlockVector blockPt = pt.toBlockVector();
         
-        if (!original.containsKey(blockPt)) {
+        //if (!original.containsKey(blockPt)) {
             original.put(blockPt, getBlock(pt));
 
             if (maxBlocks != -1 && original.size() > maxBlocks) {
                 throw new MaxChangedBlocksException(maxBlocks);
             }
-        }
+        //}
 
         current.put(pt.toBlockVector(), block);
 
@@ -213,9 +213,9 @@ public class EditSession {
         if (queued) {
             BlockVector blockPt = pt.toBlockVector();
 
-            if (current.containsKey(blockPt)) {
+            /*if (current.containsKey(blockPt)) {
                 return current.get(blockPt);
-            }
+            }*/
         }
         
         return rawGetBlock(pt);
@@ -248,7 +248,7 @@ public class EditSession {
      * Restores all blocks to their initial state.
      */
     public void undo() {
-        for (Map.Entry<BlockVector,BaseBlock> entry : original.entrySet()) {
+        for (Map.Entry<BlockVector,BaseBlock> entry : original) {
             BlockVector pt = (BlockVector)entry.getKey();
             smartSetBlock(pt, (BaseBlock)entry.getValue());
         }
@@ -259,7 +259,7 @@ public class EditSession {
      * Sets to new state.
      */
     public void redo() {
-        for (Map.Entry<BlockVector,BaseBlock> entry : current.entrySet()) {
+        for (Map.Entry<BlockVector,BaseBlock> entry : current) {
             BlockVector pt = (BlockVector)entry.getKey();
             smartSetBlock(pt, (BaseBlock)entry.getValue());
         }
@@ -328,7 +328,7 @@ public class EditSession {
     public void flushQueue() {
         if (!queued) { return; }
         
-        for (Map.Entry<BlockVector,BaseBlock> entry : queue.entrySet()) {
+        for (Map.Entry<BlockVector,BaseBlock> entry : queue) {
             BlockVector pt = (BlockVector)entry.getKey();
             rawSetBlock(pt, (BaseBlock)entry.getValue());
         }
diff --git a/src/com/sk89q/worldedit/DoubleArrayList.java b/src/com/sk89q/worldedit/DoubleArrayList.java
new file mode 100644
index 000000000..972f6baa2
--- /dev/null
+++ b/src/com/sk89q/worldedit/DoubleArrayList.java
@@ -0,0 +1,129 @@
+// $Id$
+/*
+ * WorldEdit
+ * Copyright (C) 2010 sk89q <http://www.sk89q.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package com.sk89q.worldedit;
+
+import java.util.List;
+import java.util.ArrayList;
+import java.util.Map;
+import java.util.Iterator;
+import java.util.ListIterator;
+import java.util.NoSuchElementException;
+
+/**
+ * Double array lists to work like a Map, but not really.
+ *
+ * @author sk89q
+ */
+public class DoubleArrayList<A,B> implements Iterable<Map.Entry<A,B>> {
+    /**
+     * First list.
+     */
+    private List<A> listA = new ArrayList<A>();
+    /**
+     * Second list.
+     */
+    private List<B> listB = new ArrayList<B>();
+
+    /**
+     * Add an item.
+     * 
+     * @param a
+     * @param b
+     */
+    public void put(A a, B b) {
+        listA.add(a);
+        listB.add(b);
+    }
+
+    /**
+     * Get size.
+     * @return
+     */
+    public int size() {
+        return listA.size();
+    }
+
+    /**
+     * Get an entry set.
+     *
+     * @return
+     */
+    public Iterator<Map.Entry<A,B>> iterator() {
+        return new EntryIterator<Map.Entry<A,B>>(
+                listA.listIterator(listA.size()),
+                listB.listIterator(listB.size()));
+    }
+
+    /**
+     * Entry iterator.
+     * 
+     * @param <A>
+     * @param <B>
+     */
+    public class EntryIterator<T extends Map.Entry> implements Iterator<Map.Entry<A,B>> {
+        private ListIterator<A> keyIterator;
+        private ListIterator<B> valueIterator;
+
+        public EntryIterator(ListIterator<A> keyIterator, ListIterator<B> valueIterator) {
+            this.keyIterator = keyIterator;
+            this.valueIterator = valueIterator;
+        }
+
+        public boolean hasNext() {
+            return keyIterator.hasPrevious();
+        }
+
+        public Map.Entry<A,B> next() throws NoSuchElementException {
+            return new Entry<A,B>(keyIterator.previous(), valueIterator.previous());
+        }
+
+        public void remove() {
+            throw new UnsupportedOperationException();
+        }
+    }
+
+    /**
+     * Class to masquerade as Map.Entry.
+     * 
+     * @param <A>
+     * @param <B>
+     */
+    public class Entry<A,B> implements Map.Entry<A,B> {
+        private A key;
+        private B value;
+
+        private Entry(A key, B value) {
+            this.key = key;
+            this.value = value;
+        }
+
+        public A getKey() {
+            return key;
+        }
+
+        public B getValue() {
+            return value;
+        }
+
+        public B setValue(B value) {
+            throw new UnsupportedOperationException();
+        }
+    }
+}