diff --git a/tools/cooja/java/se/sics/cooja/plugins/LogListener.java b/tools/cooja/java/se/sics/cooja/plugins/LogListener.java
index e8c79c70b..815f2b8fe 100644
--- a/tools/cooja/java/se/sics/cooja/plugins/LogListener.java
+++ b/tools/cooja/java/se/sics/cooja/plugins/LogListener.java
@@ -26,7 +26,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $Id: LogListener.java,v 1.9 2008/04/02 16:42:39 fros4943 Exp $
+ * $Id: LogListener.java,v 1.10 2008/09/01 13:01:05 fros4943 Exp $
  */
 
 package se.sics.cooja.plugins;
@@ -40,17 +40,14 @@ import java.util.*;
 import javax.swing.*;
 import org.apache.log4j.Logger;
 import org.jdom.Element;
-
 import se.sics.cooja.*;
 import se.sics.cooja.interfaces.Log;
 
 /**
  * A simple mote log listener.
- * When instantiated, is registers as a listener on all currently existing
- * motes' log interfaces. (Observe that if new motes are added to a simulation,
- * a new log listener must be created to listen to those motes also).
+ * Listens to all motes' log interfaces.
  *
- * @author Fredrik Osterlind
+ * @author Fredrik Osterlind, Niclas Finne
  */
 @ClassDescription("Log Listener")
 @PluginType(PluginType.SIM_PLUGIN)
@@ -62,9 +59,12 @@ public class LogListener extends VisPlugin {
   private Observer logObserver;
   private Simulation simulation;
 
-  private String filterText = null;
+  private String filterText = "";
   private JTextField filterTextField = null;
 
+  private String[] logCache = new String[256];
+  private int logPos;
+
   /**
    * Create a new simulation control panel.
    *
@@ -84,25 +84,38 @@ public class LogListener extends VisPlugin {
 
         Mote mote = (Mote) obj;
         Log moteLogInterface = (Log) obs;
+        String lastMessage = moteLogInterface.getLastLogMessages();
+        if (lastMessage.length() > 0 && lastMessage.charAt(lastMessage.length() - 1) == '\n') {
+          lastMessage = lastMessage.substring(0, lastMessage.length() - 1);
+        }
         String outputString = "TIME:" + simulation.getSimulationTime() + "\t";
         if (mote != null && mote.getInterfaces().getMoteID() != null) {
-          outputString = outputString.concat("ID:" + mote.getInterfaces().getMoteID().getMoteID() + "\t");
+          outputString += "ID:" + mote.getInterfaces().getMoteID().getMoteID() + "\t";
+        }
+        outputString += lastMessage;
+        if (logCache.length > 1) {
+          synchronized (logCache) {
+            logCache[logPos] = outputString;
+            logPos = (logPos + 1) % logCache.length;
+          }
         }
         // Match against filter (if any)
-        if (filterText != null && !filterText.equals("") &&
-            !moteLogInterface.getLastLogMessages().contains(filterText)) {
+        if (filterText.length() > 0 && !outputString.contains(filterText)) {
           return;
         }
 
-        outputString = outputString.concat(moteLogInterface.getLastLogMessages());
-
 
         final String str = outputString;
         SwingUtilities.invokeLater(new Runnable() {
           public void run() {
-            logTextArea.append("\n");
-            logTextArea.append(str);
-            logTextArea.setCaretPosition(logTextArea.getDocument().getLength());
+            int len = logTextArea.getDocument().getLength();
+            if (len == 0) {
+              logTextArea.append(str);
+            } else {
+              logTextArea.append('\n' + str);
+              len++;
+            }
+            logTextArea.setCaretPosition(len + str.length());
           }
         });
       }
@@ -140,15 +153,46 @@ public class LogListener extends VisPlugin {
     JPanel filterPanel = new JPanel();
     filterPanel.setLayout(new BoxLayout(filterPanel, BoxLayout.X_AXIS));
     filterTextField = new JTextField("");
-    filterPanel.add(Box.createVerticalStrut(2));
+    filterPanel.add(Box.createHorizontalStrut(2));
     filterPanel.add(new JLabel("Filter on string: "));
     filterPanel.add(filterTextField);
     filterTextField.addActionListener(new ActionListener() {
       public void actionPerformed(ActionEvent e) {
+        String oldFilterText = filterText;
         filterText = filterTextField.getText();
+        if (filterText == null) {
+          filterText = "";
+        }
+        if (!filterText.equals(oldFilterText) && logCache.length > 1) {
+          // Update from log cache
+          StringBuilder sb = new StringBuilder();
+          synchronized(logCache) { 
+            int pos = logPos;
+            int count;
+            if(logCache[pos] != null) {
+              // Log cache has wrapped
+              count = logCache.length;
+            } else {
+              // Log cache has not wrapped yet
+              count = pos;
+              pos = 0;
+            }
+            for(int i = 0; i < count; i++) {
+              if (filterText.length() == 0 || logCache[pos].contains(filterText)) {
+                if (sb.length() > 0) {
+                  sb.append('\n');
+                }
+                sb.append(logCache[pos]);
+              }
+              pos = (pos + 1) % logCache.length;
+            }
+          }
+          logTextArea.setText(sb.toString());
+          logTextArea.setCaretPosition(logTextArea.getDocument().getLength());
+        }
       }
     });
-    filterPanel.add(Box.createVerticalStrut(2));
+    filterPanel.add(Box.createHorizontalStrut(2));
     JButton saveButton;
     filterPanel.add(saveButton = new JButton("Save log"));
     saveButton.addActionListener(new ActionListener() {
@@ -193,13 +237,13 @@ public class LogListener extends VisPlugin {
       }
     });
 
-    if (gui.isVisualizedInApplet()) {
+    if (GUI.isVisualizedInApplet()) {
       saveButton.setToolTipText("Not available in applet");
       saveButton.setEnabled(false);
     }
 
     getContentPane().add(BorderLayout.CENTER, new JScrollPane(logTextArea));
-    getContentPane().add(BorderLayout.SOUTH, new JScrollPane(filterPanel));
+    getContentPane().add(BorderLayout.SOUTH, filterPanel);
 
     setTitle("Log Listener - Listening on " + nrLogs + " mote logs");
     pack();
@@ -230,6 +274,9 @@ public class LogListener extends VisPlugin {
     element = new Element("filter");
     element.setText(filterText);
     config.add(element);
+    element = new Element("history");
+    element.setText("" + logCache.length);
+    config.add(element);
 
     return config;
   }
@@ -237,14 +284,22 @@ public class LogListener extends VisPlugin {
   public boolean setConfigXML(Collection<Element> configXML, boolean visAvailable) {
 
     for (Element element : configXML) {
-      if (element.getName().equals("filter")) {
+      String name = element.getName();
+      if ("filter".equals(name)) {
         filterText = element.getText();
         filterTextField.setText(filterText);
+      } else if ("history".equals(name)) {
+        try {
+          int size = Integer.parseInt(element.getText().trim());
+          logCache = new String[size];
+          logPos = 0;
+        } catch (Exception e) {
+          // Ignore malformed history size
+        }
       }
     }
 
     return true;
   }
 
-
 }