diff --git a/core/src/net/sf/openrocket/rocketcomponent/FlightConfiguration.java b/core/src/net/sf/openrocket/rocketcomponent/FlightConfiguration.java
index 5d3ba0e07..8e65f29c7 100644
--- a/core/src/net/sf/openrocket/rocketcomponent/FlightConfiguration.java
+++ b/core/src/net/sf/openrocket/rocketcomponent/FlightConfiguration.java
@@ -64,6 +64,7 @@ public class FlightConfiguration implements FlightConfigurableParameter<FlightCo
 	final protected HashMap<Integer, StageFlags> stages = new HashMap<Integer, StageFlags>();
 	final protected HashMap<MotorConfigurationId, MotorConfiguration> motors = new HashMap<MotorConfigurationId, MotorConfiguration>();
 	final private Collection<MotorConfiguration> activeMotors = new ArrayList<MotorConfiguration>();
+	final private InstanceMap activeInstances = new InstanceMap();
 	
 	private int boundsModID = -1;
 	private BoundingBox cachedBounds = new BoundingBox();
@@ -101,6 +102,7 @@ public class FlightConfiguration implements FlightConfigurableParameter<FlightCo
 		
 		updateStages();
 		updateMotors();
+		updateActiveInstances();
 	}
 	
 	public Rocket getRocket() {
@@ -121,12 +123,14 @@ public class FlightConfiguration implements FlightConfigurableParameter<FlightCo
 			cur.active = _active;
 		}
 		updateMotors();
+		updateActiveInstances();
 	}
 
 	public void copyStages(FlightConfiguration other) {
 		for (StageFlags cur : other.stages.values())
 			stages.put(cur.stageNumber, new StageFlags(cur.stageNumber, cur.active));
 		updateMotors();
+		updateActiveInstances();
 	}
 	
 	/** 
@@ -137,6 +141,7 @@ public class FlightConfiguration implements FlightConfigurableParameter<FlightCo
 	public void clearStage(final int stageNumber) {
 		_setStageActive( stageNumber, false );
 		updateMotors();
+		updateActiveInstances();
 	}
 	
 	/**
@@ -163,6 +168,7 @@ public class FlightConfiguration implements FlightConfigurableParameter<FlightCo
 			_setStageActive(i, true);
 		}
 		updateMotors();
+		updateActiveInstances();
 	}
 	
 	/** 
@@ -174,6 +180,7 @@ public class FlightConfiguration implements FlightConfigurableParameter<FlightCo
 		_setAllStages(false);
 		_setStageActive(stageNumber, true);
 		updateMotors();
+		updateActiveInstances();
 	}
 	
 	/** 
@@ -196,9 +203,11 @@ public class FlightConfiguration implements FlightConfigurableParameter<FlightCo
 		if ((0 <= stageNumber) && (stages.containsKey(stageNumber))) {
 			StageFlags flags = stages.get(stageNumber);
 			flags.active = !flags.active;
+			updateMotors();
+			updateActiveInstances();
+			
 			return;
 		}
-		updateMotors();
 		log.error("error: attempt to retrieve via a bad stage number: " + stageNumber);
 	}
 
@@ -286,15 +295,18 @@ public class FlightConfiguration implements FlightConfigurableParameter<FlightCo
 		return toReturn;
 	}
 
+	public InstanceMap getActiveInstances() {
+		return activeInstances;
+	}
+	
 	/*
 	 * Generates a read-only, instance-aware collection of the components for this rocket & configuration
 	 * 
 	 *  TODO: swap in this function for the 'getActiveComponents() function, above;  ONLY WHEN READY / MATURE! 
 	 */
-	public InstanceMap getActiveInstances() {
-		InstanceMap contexts = new InstanceMap();
-		getActiveContextListAt( this.rocket, contexts, Transformation.IDENTITY);
-		return contexts;
+	private void updateActiveInstances() {
+		activeInstances.clear();
+		getActiveContextListAt( this.rocket, activeInstances, Transformation.IDENTITY);
 	}
 
 	private InstanceMap getActiveContextListAt(final RocketComponent component, final InstanceMap results, final Transformation parentTransform ){
@@ -401,6 +413,7 @@ public class FlightConfiguration implements FlightConfigurableParameter<FlightCo
 		
 		updateStages();
 		updateMotors();
+		updateActiveInstances();
 	}
 	
 	private void updateStages() {
@@ -531,6 +544,7 @@ public class FlightConfiguration implements FlightConfigurableParameter<FlightCo
 	public void update(){
 		updateStages();
 		updateMotors();
+		updateActiveInstances();
 	}
 	
 	///////////////  Helper methods  ///////////////
diff --git a/core/src/net/sf/openrocket/util/TestRockets.java b/core/src/net/sf/openrocket/util/TestRockets.java
index cf61a013a..632b36a63 100644
--- a/core/src/net/sf/openrocket/util/TestRockets.java
+++ b/core/src/net/sf/openrocket/util/TestRockets.java
@@ -66,7 +66,6 @@ import net.sf.openrocket.simulation.listeners.SimulationListener;
 import net.sf.openrocket.startup.Application;
 
 public class TestRockets {
-	
 	public final static FlightConfigurationId TEST_FCID_0 = new FlightConfigurationId("d010716e-ce0e-469d-ae46-190f3653ebbf");
 	public final static FlightConfigurationId TEST_FCID_1 = new FlightConfigurationId("f41bee5b-ebb8-4d92-bce7-53001577a313");
 	public final static FlightConfigurationId TEST_FCID_2 = new FlightConfigurationId("3e8d1280-53c2-4234-89a7-de215ef5cd69");
@@ -1705,30 +1704,32 @@ public class TestRockets {
 
 		// find the body and fins
 		final InstanceMap imap = rocket.getSelectedConfiguration().getActiveInstances();
-	    for(Map.Entry<RocketComponent, ArrayList<InstanceContext>> entry: imap.entrySet() ) {		
-			RocketComponent c = entry.getKey();
+		RocketComponent c = null;
+	    for(Map.Entry<RocketComponent, ArrayList<InstanceContext>> entry: imap.entrySet() ) {
+			c = entry.getKey();
 			if (c instanceof TrapezoidFinSet) {
-				final TrapezoidFinSet fins = (TrapezoidFinSet) c;
-				final BodyTube body = (BodyTube) fins.getParent();
-				body.removeChild(fins);
-				
-				// create a PodSet to hook the fins to
-				PodSet podset = new PodSet();
-				podset.setInstanceCount(fins.getFinCount());
-				
-				body.addChild(podset);
-				
-				// put a phantom body tube on the pods
-				BodyTube podBody = new BodyTube(fins.getRootChord(), 0);
-				podBody.setName("Pod Body");
-				podset.addChild(podBody);
-				
-				// change the number of fins to 1 and put the revised
-				// finset on the podbody
-				fins.setFinCount(1);
-				podBody.addChild(fins);
+				break;
 			}
 		}
+		final TrapezoidFinSet fins = (TrapezoidFinSet) c;
+		final BodyTube body = (BodyTube) fins.getParent();
+		body.removeChild(fins);
+		
+		// create a PodSet to hook the fins to
+		PodSet podset = new PodSet();
+		podset.setInstanceCount(fins.getFinCount());
+		
+		body.addChild(podset);
+		
+		// put a phantom body tube on the pods
+		BodyTube podBody = new BodyTube(fins.getRootChord(), 0);
+		podBody.setName("Pod Body");
+		podset.addChild(podBody);
+		
+		// change the number of fins to 1 and put the revised
+		// finset on the podbody
+		fins.setFinCount(1);
+		podBody.addChild(fins);
 
 		return rocket;
 	}