Index: oak-run/src/main/java/org/apache/jackrabbit/oak/explorer/Explorer.java
===================================================================
--- oak-run/src/main/java/org/apache/jackrabbit/oak/explorer/Explorer.java	(revision 1697622)
+++ oak-run/src/main/java/org/apache/jackrabbit/oak/explorer/Explorer.java	(working copy)
@@ -41,6 +41,7 @@
 import javax.swing.UIManager;
 import javax.swing.UIManager.LookAndFeelInfo;
 
+import org.apache.commons.io.IOUtils;
 import org.apache.jackrabbit.oak.plugins.segment.file.FileStore.ReadOnlyStore;
 import org.apache.jackrabbit.oak.plugins.segment.file.JournalReader;
 
@@ -67,14 +68,17 @@
         }
 
         final String path = args[0];
-        final ReadOnlyStore store = new ReadOnlyStore(new File(path));
         final boolean skipSizeCheck = args.length == 2
                 && skip.equalsIgnoreCase(args[1]);
 
         javax.swing.SwingUtilities.invokeLater(new Runnable() {
             public void run() {
                 initLF();
-                createAndShowGUI(path, store, skipSizeCheck);
+                try {
+                    createAndShowGUI(path, skipSizeCheck);
+                } catch (IOException e) {
+                    throw new RuntimeException(e);
+                }
             }
         });
     }
@@ -93,25 +97,27 @@
         }
     }
 
-    private void createAndShowGUI(final String path, final ReadOnlyStore store, boolean skipSizeCheck) {
+    private void createAndShowGUI(final String path, boolean skipSizeCheck)
+            throws IOException {
+
+        JTextArea log = new JTextArea(5, 20);
+        log.setMargin(new Insets(5, 5, 5, 5));
+        log.setLineWrap(true);
+        log.setEditable(false);
+
+        final NodeStoreTree treePanel = new NodeStoreTree(path, log, skipSizeCheck);
+
         final JFrame frame = new JFrame("Explore " + path + " @head");
         frame.addWindowListener(new java.awt.event.WindowAdapter() {
             @Override
             public void windowClosing(java.awt.event.WindowEvent windowEvent) {
-                store.close();
+                IOUtils.closeQuietly(treePanel);
                 System.exit(0);
             }
         });
 
         JPanel content = new JPanel(new GridBagLayout());
 
-        JTextArea log = new JTextArea(5, 20);
-        log.setMargin(new Insets(5, 5, 5, 5));
-        log.setLineWrap(true);
-        log.setEditable(false);
-
-        final NodeStoreTree treePanel = new NodeStoreTree(store, log, skipSizeCheck);
-
         GridBagConstraints c = new GridBagConstraints();
         c.fill = GridBagConstraints.BOTH;
         c.weightx = 1;
@@ -126,6 +132,19 @@
         JMenuBar menuBar = new JMenuBar();
         menuBar.setMargin(new Insets(2, 2, 2, 2));
 
+        JMenuItem menuReopen = new JMenuItem("Reopen");
+        menuReopen.setMnemonic(KeyEvent.VK_R);
+        menuReopen.addActionListener(new ActionListener() {
+            @Override
+            public void actionPerformed(ActionEvent ev) {
+                try {
+                    treePanel.reopen();
+                } catch (IOException e) {
+                    throw new RuntimeException(e);
+                }
+            }
+        });
+
         JMenuItem menuCompaction = new JMenuItem("Time Machine");
         menuCompaction.setMnemonic(KeyEvent.VK_T);
         menuCompaction.addActionListener(new ActionListener() {
@@ -221,6 +240,8 @@
             }
         });
 
+        menuBar.add(menuReopen);
+        menuBar.add(new JSeparator(JSeparator.VERTICAL));
         menuBar.add(menuCompaction);
         menuBar.add(new JSeparator(JSeparator.VERTICAL));
         menuBar.add(menuRefs);
Index: oak-run/src/main/java/org/apache/jackrabbit/oak/explorer/NodeStoreTree.java
===================================================================
--- oak-run/src/main/java/org/apache/jackrabbit/oak/explorer/NodeStoreTree.java	(revision 1697622)
+++ oak-run/src/main/java/org/apache/jackrabbit/oak/explorer/NodeStoreTree.java	(working copy)
@@ -24,6 +24,7 @@
 import static com.google.common.escape.Escapers.builder;
 
 import java.awt.GridLayout;
+import java.io.Closeable;
 import java.io.File;
 import java.io.IOException;
 import java.util.Collections;
@@ -67,9 +68,11 @@
 import org.apache.jackrabbit.oak.spi.state.ChildNodeEntry;
 import org.apache.jackrabbit.oak.spi.state.NodeState;
 
-public class NodeStoreTree extends JPanel implements TreeSelectionListener {
+public class NodeStoreTree extends JPanel implements TreeSelectionListener,
+        Closeable {
 
-    private final ReadOnlyStore store;
+    private final String path;
+    private ReadOnlyStore store;
 
     private DefaultTreeModel treeModel;
     private final JTree tree;
@@ -81,32 +84,31 @@
     // TODO make this configurable
     private final boolean cacheNodeState = false;
 
-    public NodeStoreTree(ReadOnlyStore store, JTextArea log, boolean skipSizeCheck) {
+    public NodeStoreTree(String path, JTextArea log, boolean skipSizeCheck)
+            throws IOException {
         super(new GridLayout(1, 0));
-        this.store = store;
+        this.path = path;
         this.log = log;
-
-        this.index = store.getTarReaderIndex();
-        this.sizeCache = new HashMap<RecordIdKey, Long[]>();
         this.skipSizeCheck = skipSizeCheck;
 
-        DefaultMutableTreeNode rootNode = new DefaultMutableTreeNode(
-                new NamePathModel("/", "/", store.getHead(), sizeCache,
-                        skipSizeCheck, store, cacheNodeState), true);
-        treeModel = new DefaultTreeModel(rootNode);
-        addChildren(rootNode);
-
-        tree = new JTree(treeModel);
+        tree = new JTree();
         tree.getSelectionModel().setSelectionMode(
                 TreeSelectionModel.SINGLE_TREE_SELECTION);
         tree.setShowsRootHandles(true);
         tree.addTreeSelectionListener(this);
         tree.setExpandsSelectedPaths(true);
 
+        refreshStore();
+        refreshModel();
+
         JScrollPane scrollPane = new JScrollPane(tree);
         add(scrollPane);
     }
 
+    private void refreshStore() throws IOException {
+        this.store = new ReadOnlyStore(new File(path));
+    }
+
     private void refreshModel() {
         index = store.getTarReaderIndex();
         sizeCache = new HashMap<RecordIdKey, Long[]>();
@@ -115,6 +117,13 @@
                         skipSizeCheck, store, cacheNodeState), true);
         treeModel = new DefaultTreeModel(rootNode);
         addChildren(rootNode);
+        tree.setModel(treeModel);
+    }
+
+    public void reopen() throws IOException {
+        close();
+        refreshStore();
+        refreshModel();
     }
 
     @Override
@@ -802,4 +811,9 @@
 
     }
 
+    @Override
+    public void close() throws IOException {
+        store.close();
+    }
+
 }