diff --git a/org.adempiere.ui.zk/WEB-INF/src/org/adempiere/webui/adwindow/ADSortTab.java b/org.adempiere.ui.zk/WEB-INF/src/org/adempiere/webui/adwindow/ADSortTab.java
index 14348e73b1..b83e8f0b73 100644
--- a/org.adempiere.ui.zk/WEB-INF/src/org/adempiere/webui/adwindow/ADSortTab.java
+++ b/org.adempiere.ui.zk/WEB-INF/src/org/adempiere/webui/adwindow/ADSortTab.java
@@ -375,6 +375,13 @@ public class ADSortTab extends Panel implements IADTabpanel
 		vbox.appendChild(bDown);
 		vbox.setWidth("46px");
 		hlayout.appendChild(vbox);
+		
+		addEventListener(ON_ACTIVATE_EVENT, new EventListener<Event>() {
+			@Override
+			public void onEvent(Event event) throws Exception {
+				removeAttribute(ATTR_ON_ACTIVATE_POSTED);
+			}
+		});
 	}	//	Init
 
 	/* (non-Javadoc)
@@ -831,8 +838,16 @@ public class ADSortTab extends Panel implements IADTabpanel
 	}
 
 	public void activate(boolean b) {
-		active  = b;
-		if (b && !uiCreated) createUI();
+		if (b) {
+	    	if (getAttribute(ATTR_ON_ACTIVATE_POSTED) != null) {
+	    		return;
+	    	}
+	    	
+	    	setAttribute(ATTR_ON_ACTIVATE_POSTED, Boolean.TRUE);
+    	}
+		
+		Event event = new Event(ON_ACTIVATE_EVENT, this, b);
+        Events.postEvent(event);
 	}
 
 	public void createUI() {
diff --git a/org.adempiere.ui.zk/WEB-INF/src/org/adempiere/webui/adwindow/ADTabpanel.java b/org.adempiere.ui.zk/WEB-INF/src/org/adempiere/webui/adwindow/ADTabpanel.java
index 29f0a5fde2..2f7da2adf7 100644
--- a/org.adempiere.ui.zk/WEB-INF/src/org/adempiere/webui/adwindow/ADTabpanel.java
+++ b/org.adempiere.ui.zk/WEB-INF/src/org/adempiere/webui/adwindow/ADTabpanel.java
@@ -26,7 +26,6 @@ import java.util.Map.Entry;
 import java.util.logging.Level;
 
 import org.adempiere.webui.LayoutUtils;
-import org.adempiere.webui.apps.AEnv;
 import org.adempiere.webui.component.Borderlayout;
 import org.adempiere.webui.component.Column;
 import org.adempiere.webui.component.Columns;
@@ -104,12 +103,8 @@ DataStatusListener, IADTabpanel
 {
 	public static final String ON_SWITCH_VIEW_EVENT = "onSwitchView";
 
-	public static final String ON_ACTIVATE_EVENT = "onActivate";
-
 	public static final String ON_DYNAMIC_DISPLAY_EVENT = "onDynamicDisplay";
 	
-	private static final String ATTR_ON_ACTIVATE_POSTED = "org.adempiere.webui.adwindow.ADTabpanel.onActivatePosted";
-
 	/**
 	 * 
 	 */
diff --git a/org.adempiere.ui.zk/WEB-INF/src/org/adempiere/webui/adwindow/IADTabpanel.java b/org.adempiere.ui.zk/WEB-INF/src/org/adempiere/webui/adwindow/IADTabpanel.java
index 6c3cf35e16..226c621fc5 100644
--- a/org.adempiere.ui.zk/WEB-INF/src/org/adempiere/webui/adwindow/IADTabpanel.java
+++ b/org.adempiere.ui.zk/WEB-INF/src/org/adempiere/webui/adwindow/IADTabpanel.java
@@ -23,6 +23,9 @@ import org.zkoss.zk.ui.Component;
  */
 public interface IADTabpanel extends Component, Evaluatee {
 
+	public static final String ON_ACTIVATE_EVENT = "onActivate";
+	public static final String ATTR_ON_ACTIVATE_POSTED = "org.adempiere.webui.adwindow.IADTabpanel.onActivatePosted";
+
 	/**
 	 * @return display logic
 	 */