diff -r a41745e3828d -r e837e1e4b282 GUI/HardwareNode.cs
--- a/GUI/HardwareNode.cs	Sun Jan 01 15:46:42 2012 +0000
+++ b/GUI/HardwareNode.cs	Sun Jan 01 17:12:34 2012 +0000
@@ -108,9 +108,14 @@
             if (n != null && n.Sensor == sensor)
               sensorNode = n;
           }
-          typeNode.Nodes.Remove(sensorNode);
-          UpdateNode(typeNode);
+          if (sensorNode != null) {
+            sensorNode.PlotSelectionChanged -= SensorPlotSelectionChanged;
+            typeNode.Nodes.Remove(sensorNode);
+            UpdateNode(typeNode);
+          }
         }
+      if (PlotSelectionChanged != null)
+        PlotSelectionChanged(this, null);
     }
 
     private void InsertSorted(Node node, ISensor sensor) {
@@ -119,15 +124,25 @@
         ((SensorNode)node.Nodes[i]).Sensor.Index < sensor.Index)
         i++;
       SensorNode sensorNode = new SensorNode(sensor, settings, unitManager);
+      sensorNode.PlotSelectionChanged += SensorPlotSelectionChanged;
       node.Nodes.Insert(i, sensorNode);
     }
 
+    private void SensorPlotSelectionChanged(object sender, EventArgs e) {
+      if (PlotSelectionChanged != null)
+        PlotSelectionChanged(this, null);
+    }
+
     private void SensorAdded(ISensor sensor) {
       foreach (TypeNode typeNode in typeNodes)
         if (typeNode.SensorType == sensor.SensorType) {
           InsertSorted(typeNode, sensor);
           UpdateNode(typeNode);          
         }
-    }    
+      if (PlotSelectionChanged != null)
+        PlotSelectionChanged(this, null);
+    }
+
+    public event EventHandler PlotSelectionChanged;
   }
 }