diff --git a/zkwebui/WEB-INF/src/org/adempiere/webui/component/GridPanel.java b/zkwebui/WEB-INF/src/org/adempiere/webui/component/GridPanel.java
index 8d33783dc2..c3aff88489 100644
--- a/zkwebui/WEB-INF/src/org/adempiere/webui/component/GridPanel.java
+++ b/zkwebui/WEB-INF/src/org/adempiere/webui/component/GridPanel.java
@@ -20,6 +20,7 @@ import javax.swing.table.AbstractTableModel;
 
 import org.adempiere.webui.LayoutUtils;
 import org.adempiere.webui.editor.WEditor;
+import org.adempiere.webui.panel.AbstractADWindowPanel;
 import org.adempiere.webui.util.SortComparator;
 import org.compiere.model.GridField;
 import org.compiere.model.GridTab;
@@ -52,9 +53,9 @@ import org.zkoss.zul.event.ZulEvents;
 public class GridPanel extends Borderlayout implements EventListener
 {
 	/**
-	 * 
+	 * generated serial version ID
 	 */
-	private static final long serialVersionUID = -8735897196875342427L;
+	private static final long serialVersionUID = -7151423393713654553L;
 
 	private static final int MIN_COLUMN_WIDTH = 100;
 
@@ -91,6 +92,8 @@ public class GridPanel extends Borderlayout implements EventListener
 
 	private String columnOnClick;
 
+	private AbstractADWindowPanel windowPanel;
+
 	public static final String PAGE_SIZE_KEY = "ZK_PAGING_SIZE";
 
 	public static final String MODE_LESS_KEY = "ZK_GRID_EDIT_MODELESS";
@@ -328,6 +331,7 @@ public class GridPanel extends Borderlayout implements EventListener
 			renderer.stopEditing(false);
 		renderer = new GridTabRowRenderer(gridTab, windowNo);
 		renderer.setGridPanel(this);
+		renderer.setADWindowPanel(windowPanel);
 
 		listbox.setRowRenderer(renderer);
 		listbox.setModel(listModel);
@@ -608,6 +612,9 @@ public class GridPanel extends Borderlayout implements EventListener
 		return false;
 	}
 
+	/**
+	 * @param columnName
+	 */
 	public void setFocusToField(String columnName) {
 		boolean found = false;
 		for (WEditor editor : renderer.getEditors()) {
@@ -620,4 +627,13 @@ public class GridPanel extends Borderlayout implements EventListener
 			}
 		}
 	}
+
+	/**
+	 * @param winPanel
+	 */
+	public void setADWindowPanel(AbstractADWindowPanel winPanel) {
+		windowPanel = winPanel;
+		if (renderer != null)
+			renderer.setADWindowPanel(windowPanel);
+	}
 }
diff --git a/zkwebui/WEB-INF/src/org/adempiere/webui/component/GridTabRowRenderer.java b/zkwebui/WEB-INF/src/org/adempiere/webui/component/GridTabRowRenderer.java
index 70e3fded47..ce8ac71a1f 100644
--- a/zkwebui/WEB-INF/src/org/adempiere/webui/component/GridTabRowRenderer.java
+++ b/zkwebui/WEB-INF/src/org/adempiere/webui/component/GridTabRowRenderer.java
@@ -79,6 +79,7 @@ public class GridTabRowRenderer implements RowRenderer, RowRendererExt, Renderer
 	private Object[] currentValues;
 	private boolean editing = false;
 	private int currentRowIndex = -1;
+	private AbstractADWindowPanel m_windowPanel;
 
 	/**
 	 *
@@ -96,12 +97,19 @@ public class GridTabRowRenderer implements RowRenderer, RowRendererExt, Renderer
 		if (editor != null)  {
 			if (editor instanceof WButtonEditor)
             {
-				Object window = SessionManager.getAppDesktop().findWindow(windowNo);
-            	if (window != null && window instanceof ADWindow)
-            	{
-            		AbstractADWindowPanel windowPanel = ((ADWindow)window).getADWindowPanel();
-            		((WButtonEditor)editor).addActionListener(windowPanel);
-            	}
+				if (m_windowPanel != null)
+				{
+					((WButtonEditor)editor).addActionListener(m_windowPanel);	
+				}
+				else
+				{
+					Object window = SessionManager.getAppDesktop().findWindow(windowNo);
+	            	if (window != null && window instanceof ADWindow)
+	            	{
+	            		AbstractADWindowPanel windowPanel = ((ADWindow)window).getADWindowPanel();
+	            		((WButtonEditor)editor).addActionListener(windowPanel);
+	            	}
+				}
             }
 			else
 			{
@@ -150,8 +158,6 @@ public class GridTabRowRenderer implements RowRenderer, RowRendererExt, Renderer
 		}
 		else if (gridField.isLookup())
     	{
-			if (value == null) return "";
-
 			if (lookupCache != null)
 			{
 				Map<Object, String> cache = lookupCache.get(gridField.getColumnName());
@@ -583,7 +589,17 @@ public class GridTabRowRenderer implements RowRenderer, RowRendererExt, Renderer
 		}
 	}
 
+	/**
+	 * @return boolean
+	 */
 	public boolean isEditing() {
 		return editing;
 	}
+
+	/**
+	 * @param windowPanel
+	 */
+	public void setADWindowPanel(AbstractADWindowPanel windowPanel) {
+		this.m_windowPanel = windowPanel;
+	}
 }
diff --git a/zkwebui/WEB-INF/src/org/adempiere/webui/panel/ADTabpanel.java b/zkwebui/WEB-INF/src/org/adempiere/webui/panel/ADTabpanel.java
index 6e18c2f15e..10243f37a5 100644
--- a/zkwebui/WEB-INF/src/org/adempiere/webui/panel/ADTabpanel.java
+++ b/zkwebui/WEB-INF/src/org/adempiere/webui/panel/ADTabpanel.java
@@ -228,6 +228,7 @@ DataStatusListener, IADTabpanel, VetoableChangeListener
         this.appendChild(listPanel);
         listPanel.setVisible(false);
         listPanel.setWindowNo(windowNo);
+        listPanel.setADWindowPanel(winPanel);
 
         gridTab.getTableModel().addVetoableChangeListener(this);
     }