diff --git a/ganttzk/src/main/java/org/zkoss/ganttz/TaskComponent.java b/ganttzk/src/main/java/org/zkoss/ganttz/TaskComponent.java
index 07e6e1c27..aa50d3739 100644
--- a/ganttzk/src/main/java/org/zkoss/ganttz/TaskComponent.java
+++ b/ganttzk/src/main/java/org/zkoss/ganttz/TaskComponent.java
@@ -152,7 +152,9 @@ public class TaskComponent extends Div implements AfterCompose {
                 if (command.equals("onUpdatePosition")){
                     ta = retrieveTaskComponent(request);
 
-                    ta.doUpdatePosition((Integer) retrieveData(request, "left"), (Integer) retrieveData(request, "top"));
+                    ta.doUpdatePosition(
+                            toInteger(retrieveData(request, "left")),
+                            toInteger(retrieveData(request, "top")));
                     Events.postEvent(new Event(getId(), ta, request.getData()));
 
                     return true;
@@ -160,7 +162,7 @@ public class TaskComponent extends Div implements AfterCompose {
                 if (command.equals("onUpdateWidth")){
                     ta = retrieveTaskComponent(request);
 
-                    ta.doUpdateSize((Integer) retrieveData(request, "width"));
+                    ta.doUpdateSize(toInteger(retrieveData(request, "width")));
                     Events.postEvent(new Event(getId(), ta, request.getData()));
 
                     return true;
@@ -176,6 +178,10 @@ public class TaskComponent extends Div implements AfterCompose {
                 return false;
             }
 
+            private int toInteger(Object valueFromRequestData) {
+                return ((Number) valueFromRequestData).intValue();
+            }
+
             private TaskComponent retrieveTaskComponent(AuRequest request){
                 final TaskComponent ta = (TaskComponent) request.getComponent();