=== modified file 'src/com/goldencode/p2j/ui/client/WidgetRegistry.java'
--- src/com/goldencode/p2j/ui/client/WidgetRegistry.java	2016-02-17 19:32:15 +0000
+++ src/com/goldencode/p2j/ui/client/WidgetRegistry.java	2016-03-04 20:54:30 +0000
@@ -55,6 +55,7 @@
 
 import java.util.*;
 import java.util.concurrent.locks.*;
+import java.util.function.Predicate;
 import java.util.logging.*;
 
 import com.goldencode.p2j.ui.*;
@@ -84,22 +85,22 @@
    private final ReadWriteLock lock = new ReentrantReadWriteLock();
    
    /**
-    * Returns a nearest widget's ancestor having a given type.
+    * Returns a nearest widget's ancestor that satisfies the target filter condition.
     * 
     * @param    w
     *           The target widget that can have an ancestor of a given type.
-    * @param    type
-    *           The specified type condition.
+    * @param    filter
+    *           The target filter condition.
     * 
-    * @return   The ancestor having the specified type or null if there are no widgets
-    *           satisfied this condition.
+    * @return   The ancestor satisfied the target filter condition or null if there are no
+    *           widgets satisfied this condition.
     */
-   public static Widget findAncestor(Widget w, Class type)
+   public static Widget findAncestor(Widget w, Predicate<Widget> filter)
    {
       Widget c = w;
       while (c != null)
       {
-         if (c.getClass().equals(type))
+         if (filter.test(c))
          {
             return c;
          }

=== modified file 'src/com/goldencode/p2j/ui/client/gui/FrameGuiImpl.java'
--- src/com/goldencode/p2j/ui/client/gui/FrameGuiImpl.java	2016-02-24 17:44:15 +0000
+++ src/com/goldencode/p2j/ui/client/gui/FrameGuiImpl.java	2016-03-06 15:27:27 +0000
@@ -742,7 +742,8 @@
   @Override
    protected MouseHoverAction createMouseHoverAction()
    {
-      return new MouseHoverAction(this)
+      // frame scroll component is the smallest widget that catch the mouse input and has an id. 
+      return new MouseHoverAction(this, this.frameScroll.getId().asInt())
       {
          @Override
          protected MousePtrWrapper parentCursor()

=== modified file 'src/com/goldencode/p2j/ui/client/gui/driver/swing/SwingMouseHandler.java'
--- src/com/goldencode/p2j/ui/client/gui/driver/swing/SwingMouseHandler.java	2016-02-18 11:36:28 +0000
+++ src/com/goldencode/p2j/ui/client/gui/driver/swing/SwingMouseHandler.java	2016-03-06 15:19:42 +0000
@@ -29,11 +29,13 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.function.Predicate;
 
 import com.goldencode.p2j.security.*;
 import com.goldencode.p2j.ui.WidgetId;
 import com.goldencode.p2j.ui.client.*;
 import com.goldencode.p2j.ui.client.event.*;
+import com.goldencode.p2j.ui.client.gui.FrameGuiImpl;
 import com.goldencode.p2j.ui.client.gui.driver.*;
 import com.goldencode.p2j.ui.client.widget.*;
 
@@ -161,7 +163,7 @@
          {
             Widget<?> mouseSource = findMouseSource(e);
             lastHoveredWidget = mouseSource;
-      
+            
             if (!processAction(e))
             {
                SwingMouseHandler.super.mouseEntered(e);
@@ -375,6 +377,7 @@
       }
       
       Widget<?> mouseSource = window.findMouseSource(new MouseEvt(e, window));
+      
       return mouseSource;
    }
 
@@ -415,7 +418,17 @@
          return false;
       }
       
-      WidgetId wid = UiUtils.getWidgetId(widget);
+      // find widget in its ancestor's hierarchy that has an id 
+      Widget parent = WidgetRegistry.findAncestor(widget, new Predicate<Widget>()
+      {
+         @Override
+         public boolean test(Widget t)
+         {
+            return UiUtils.getWidgetId(t) != null;
+         }
+      });
+      
+      WidgetId wid = UiUtils.getWidgetId(parent);
       
       if (wid == null)
       {

=== modified file 'src/com/goldencode/p2j/ui/client/gui/driver/web/WebMouseHandler.java'
--- src/com/goldencode/p2j/ui/client/gui/driver/web/WebMouseHandler.java	2016-03-03 16:10:57 +0000
+++ src/com/goldencode/p2j/ui/client/gui/driver/web/WebMouseHandler.java	2016-03-04 20:57:16 +0000
@@ -20,6 +20,7 @@
 package com.goldencode.p2j.ui.client.gui.driver.web;
 
 import java.awt.event.MouseEvent;
+import java.util.function.Predicate;
 
 import com.goldencode.p2j.ui.client.*;
 import com.goldencode.p2j.ui.client.gui.*;
@@ -63,7 +64,14 @@
             }
             else
             {
-               Widget editor = WidgetRegistry.findAncestor(target, EditorGuiImpl.class);
+               Widget editor = WidgetRegistry.findAncestor(target, new Predicate<Widget>()
+               {
+                  @Override
+                  public boolean test(Widget t)
+                  {
+                     return EditorGuiImpl.class.equals(t.getClass());
+                  }
+               });
                if (editor != null && editor.getId() != null)
                {
                   widgetId = editor.getId().asInt();