diff --git a/tools/cooja/apps/mrm/java/se/sics/mrm/MRM.java b/tools/cooja/apps/mrm/java/se/sics/mrm/MRM.java
index 72f258d28..e44264579 100644
--- a/tools/cooja/apps/mrm/java/se/sics/mrm/MRM.java
+++ b/tools/cooja/apps/mrm/java/se/sics/mrm/MRM.java
@@ -26,7 +26,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $Id: MRM.java,v 1.11 2009/11/25 15:43:03 fros4943 Exp $
+ * $Id: MRM.java,v 1.12 2010/12/02 15:25:50 fros4943 Exp $
  */
 
 package se.sics.mrm;
@@ -72,6 +72,7 @@ public class MRM extends AbstractRadioMedium {
 
   private Random random = null;
 
+  private Simulation sim;
   /**
    * Notifies observers when this radio medium has changed settings.
    */
@@ -82,16 +83,26 @@ public class MRM extends AbstractRadioMedium {
    */
   public MRM(Simulation simulation) {
     super(simulation);
+    sim = simulation;
+    
     random = simulation.getRandomGenerator();
 
     // Create the channel model
     currentChannelModel = new ChannelModel();
 
-    // Register temporary plugins
-    simulation.getGUI().registerTemporaryPlugin(AreaViewer.class);
-    simulation.getGUI().registerTemporaryPlugin(FormulaViewer.class);
+  	/* Register plugins */
+    sim.getGUI().registerPlugin(AreaViewer.class);
+    sim.getGUI().registerPlugin(FormulaViewer.class);
   }
 
+  public void removed() {
+  	super.removed();
+
+  	/* Unregister plugins */
+    sim.getGUI().unregisterPlugin(AreaViewer.class);
+    sim.getGUI().unregisterPlugin(FormulaViewer.class);
+  }
+  
   public MRMRadioConnection createConnections(Radio sendingRadio) {
     Position sendingPosition = sendingRadio.getPosition();
     MRMRadioConnection newConnection = new MRMRadioConnection(sendingRadio);
diff --git a/tools/cooja/java/se/sics/cooja/RadioMedium.java b/tools/cooja/java/se/sics/cooja/RadioMedium.java
index 5a30ed2f9..69dad8494 100644
--- a/tools/cooja/java/se/sics/cooja/RadioMedium.java
+++ b/tools/cooja/java/se/sics/cooja/RadioMedium.java
@@ -26,7 +26,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $Id: RadioMedium.java,v 1.9 2010/02/03 15:49:25 fros4943 Exp $
+ * $Id: RadioMedium.java,v 1.10 2010/12/02 15:25:50 fros4943 Exp $
  */
 
 package se.sics.cooja;
@@ -165,4 +165,10 @@ public abstract class RadioMedium {
         .getConstructor(new Class[] { Simulation.class });
     return (RadioMedium) constr.newInstance(new Object[] { simulation });
   }
+  
+  /**
+   * Called when radio medium is removed. 
+   */
+  public void removed() {
+  }
 }
diff --git a/tools/cooja/java/se/sics/cooja/Simulation.java b/tools/cooja/java/se/sics/cooja/Simulation.java
index 0fabe7b66..f6705211d 100644
--- a/tools/cooja/java/se/sics/cooja/Simulation.java
+++ b/tools/cooja/java/se/sics/cooja/Simulation.java
@@ -24,7 +24,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
- * $Id: Simulation.java,v 1.67 2010/10/12 10:58:31 fros4943 Exp $
+ * $Id: Simulation.java,v 1.68 2010/12/02 15:25:49 fros4943 Exp $
  */
 
 package se.sics.cooja;
@@ -732,6 +732,11 @@ public class Simulation extends Observable implements Runnable {
    * This method is called just before the simulation is removed.
    */
   public void removed() {
+  	/* Remove radio medium */
+  	if (currentRadioMedium != null) {
+  		currentRadioMedium.removed();
+  	}
+  	
     /* Remove all motes */
     Mote[] motes = getMotes();
     for (Mote m: motes) {
diff --git a/tools/cooja/java/se/sics/cooja/radiomediums/DirectedGraphMedium.java b/tools/cooja/java/se/sics/cooja/radiomediums/DirectedGraphMedium.java
index ed7b22c1c..adbbaac4b 100644
--- a/tools/cooja/java/se/sics/cooja/radiomediums/DirectedGraphMedium.java
+++ b/tools/cooja/java/se/sics/cooja/radiomediums/DirectedGraphMedium.java
@@ -26,7 +26,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $Id: DirectedGraphMedium.java,v 1.7 2010/11/10 13:09:01 fros4943 Exp $
+ * $Id: DirectedGraphMedium.java,v 1.8 2010/12/02 15:25:50 fros4943 Exp $
  */
 
 package se.sics.cooja.radiomediums;
@@ -88,12 +88,19 @@ public class DirectedGraphMedium extends AbstractRadioMedium {
 
     requestEdgeAnalysis();
 
-    /* Register plugin.
-     * TODO Should be unregistered when radio medium is removed */
-    simulation.getGUI().registerTemporaryPlugin(DGRMConfigurator.class);
+  	/* Register plugin and visualizer skin */
+    simulation.getGUI().registerPlugin(DGRMConfigurator.class);
     Visualizer.registerVisualizerSkin(DGRMVisualizerSkin.class);
-}
+  }
 
+  public void removed() {
+  	super.removed();
+
+  	/* Unregister plugin and visualizer skin */
+    simulation.getGUI().unregisterPlugin(DGRMConfigurator.class);
+    Visualizer.unregisterVisualizerSkin(DGRMVisualizerSkin.class);
+  }
+  
   public void addEdge(Edge e) {
     edges.add(e);
     requestEdgeAnalysis();