diff --git a/navalplanner-gantt-zk/src/main/java/org/zkoss/ganttz/Planner.java b/navalplanner-gantt-zk/src/main/java/org/zkoss/ganttz/Planner.java
index da2920eee..62073b6ab 100644
--- a/navalplanner-gantt-zk/src/main/java/org/zkoss/ganttz/Planner.java
+++ b/navalplanner-gantt-zk/src/main/java/org/zkoss/ganttz/Planner.java
@@ -20,6 +20,8 @@ public class Planner extends XulElement implements AfterCompose {
 
     private DependencyRemovedListener dependencyRemovedListener;
 
+    private TaskRemovedListener taskRemovedListener;
+
     public Planner() {
     }
 
@@ -85,12 +87,13 @@ public class Planner extends XulElement implements AfterCompose {
             }
         };
         taskList.addDependencyListener(dependencyAddedListener);
-        taskList.addTaskRemovedListener(new TaskRemovedListener() {
+        taskRemovedListener = new TaskRemovedListener() {
             @Override
             public void taskRemoved(Task taskRemoved) {
                 dependencyRegistry.remove(taskRemoved.getTaskBean());
             }
-        });
+        };
+        taskList.addTaskRemovedListener(taskRemovedListener);
         dependencyRemovedListener = new DependencyRemovedListener() {
 
             @Override
diff --git a/navalplanner-gantt-zk/src/main/java/org/zkoss/ganttz/util/DependencyRegistry.java b/navalplanner-gantt-zk/src/main/java/org/zkoss/ganttz/util/DependencyRegistry.java
index 7aadad658..2980a5ffc 100644
--- a/navalplanner-gantt-zk/src/main/java/org/zkoss/ganttz/util/DependencyRegistry.java
+++ b/navalplanner-gantt-zk/src/main/java/org/zkoss/ganttz/util/DependencyRegistry.java
@@ -76,13 +76,18 @@ public class DependencyRegistry {
     }
 
     public void remove(TaskBean task) {
+        List<RulesEnforcer> outgoing = getOutgoing(task);
         graph.removeVertex(task);
         rulesEnforcersByTask.remove(task);
-        updateOutgoing(task);
+        update(outgoing);
     }
 
     private void updateOutgoing(TaskBean task) {
-        for (RulesEnforcer rulesEnforcer : getOutgoing(task)) {
+        update(getOutgoing(task));
+    }
+
+    private void update(List<RulesEnforcer> outgoing) {
+        for (RulesEnforcer rulesEnforcer : outgoing) {
             rulesEnforcer.update();
         }
     }