Index: E:/workspace-3.3.1.1/plugins/org.jboss.tools.vpe.xulrunner/src/org/jboss/tools/vpe/xulrunner/browser/XulRunnerBrowser.java
===================================================================
--- E:/workspace-3.3.1.1/plugins/org.jboss.tools.vpe.xulrunner/src/org/jboss/tools/vpe/xulrunner/browser/XulRunnerBrowser.java	(revision 5437)
+++ E:/workspace-3.3.1.1/plugins/org.jboss.tools.vpe.xulrunner/src/org/jboss/tools/vpe/xulrunner/browser/XulRunnerBrowser.java	(working copy)
@@ -153,6 +153,10 @@
 		browser.addListener(eventType, listener);
 	}
 	
+	public void removeListener(int eventType, Listener listener) {
+		browser.removeListener(eventType, listener);
+	}
+	
 	/**
 	 * Decorate Widget.dispose()
 	 */
@@ -158,7 +162,7 @@
 	 */
 	public void dispose() {
 		browser.dispose();
-		
+		browser = null;
 	}
 	
 	public static String getXulRunnerBundle() {
@@ -416,4 +420,8 @@
 	public Browser getBrowser() {
 		return browser;
 	}
+	
+	protected void onDispose() {
+		
+	}
 }
Index: E:/workspace-3.3.1.1/plugins/org.jboss.tools.vpe.xulrunner/src/org/jboss/tools/vpe/xulrunner/editor/XulRunnerEditor.java
===================================================================
--- E:/workspace-3.3.1.1/plugins/org.jboss.tools.vpe.xulrunner/src/org/jboss/tools/vpe/xulrunner/editor/XulRunnerEditor.java	(revision 5437)
+++ E:/workspace-3.3.1.1/plugins/org.jboss.tools.vpe.xulrunner/src/org/jboss/tools/vpe/xulrunner/editor/XulRunnerEditor.java	(working copy)
@@ -15,6 +15,8 @@
 
 import org.eclipse.core.runtime.Platform;
 import org.eclipse.swt.SWT;
+import org.eclipse.swt.events.DisposeEvent;
+import org.eclipse.swt.events.DisposeListener;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Display;
 import org.eclipse.swt.widgets.Event;
@@ -38,9 +40,13 @@
 import org.mozilla.interfaces.nsIDragSession;
 import org.mozilla.interfaces.nsIInterfaceRequestor;
 import org.mozilla.interfaces.nsISelection;
+import org.mozilla.interfaces.nsISelectionListener;
+import org.mozilla.interfaces.nsISelectionPrivate;
 import org.mozilla.interfaces.nsIServiceManager;
 import org.mozilla.interfaces.nsISupports;
+import org.mozilla.interfaces.nsITooltipListener;
 import org.mozilla.interfaces.nsITransferable;
+import org.mozilla.interfaces.nsIWebProgressListener;
 import org.mozilla.xpcom.Mozilla;
 import org.mozilla.xpcom.XPCOMException;
 
@@ -101,6 +107,17 @@
 	 */
 	private boolean scrollRegtangleFlag = false;
 
+	private nsISelectionListener selectionListener;
+
+	private Listener eventListenet = new Listener() {
+
+		public void handleEvent(Event event) {
+			Display.getCurrent().asyncExec(new Thread(){
+				public void run(){
+					showSelectionRectangle();
+				}
+			});
+		}};
 	/**
 	 * @param parent
 	 * @throws XulRunnerException
@@ -107,16 +124,34 @@
 	 */
 	public XulRunnerEditor(Composite parent) throws XulRunnerException {
 		super(parent);
-		
-		Listener eventListenet = new Listener() {
+		getBrowser().addDisposeListener(new DisposeListener() {
 
-			public void handleEvent(Event event) {
-				Display.getCurrent().asyncExec(new Thread(){
-					public void run(){
-						showSelectionRectangle();
-					}
-				});
-			}};
+			public void widgetDisposed(DisposeEvent e) {
+				getWebBrowser().removeWebBrowserListener(XulRunnerEditor.this, nsIWebProgressListener.NS_IWEBPROGRESSLISTENER_IID);
+				getWebBrowser().removeWebBrowserListener(XulRunnerEditor.this, nsITooltipListener.NS_ITOOLTIPLISTENER_IID);
+				if (selectionListener != null) {
+					nsISelection selection = getSelection();
+					nsISelectionPrivate selectionPrivate = (nsISelectionPrivate) selection.queryInterface(nsISelectionPrivate.NS_ISELECTIONPRIVATE_IID);
+					selectionPrivate.removeSelectionListener(selectionListener);
+				}
+				if (resizeListener != null)
+					getIXulRunnerVpeResizer().removeResizeListener(resizeListener);
+				xulRunnerVpeResizer = null;
+				resizeListener = null;
+				if (eventListenet != null) {
+					removeListener(SWT.Paint, eventListenet);
+					removeListener(SWT.Show, eventListenet);
+					removeListener(SWT.FocusIn, eventListenet);
+					removeListener(SWT.Selection, eventListenet);
+					removeListener(SWT.Paint, eventListenet);
+					eventListenet = null;
+				}
+				getBrowser().removeDisposeListener(this);
+				onDispose();
+			}
+			
+		});
+		
 //			addListener(SWT.Activate, eventListenet);
 			addListener(SWT.Paint, eventListenet);
 			//Commented by Max Areshkau (bug on Mac OS X10.4 
@@ -411,7 +446,7 @@
 	try {
 		
 		 parentElement = (nsIDOMElement) element.getParentNode().queryInterface(nsIDOMElement.NS_IDOMELEMENT_IID);
-	} catch (XPCOMException ex) {
+	} catch (Exception ex) {
 		// if parent node isn't nsIDOMElement just return null;
 		return null;
 	}
@@ -421,7 +456,11 @@
 				return parentElement;
 			}else {
 			
-				parentElement=(nsIDOMElement) parentElement.getParentNode() ;
+				try {
+					parentElement=(nsIDOMElement) parentElement.getParentNode() ;
+				} catch (Exception e) {
+					return null;
+				}
 			}
 		}
 		return parentElement;
@@ -508,6 +547,15 @@
 		
 		getIFlasher().scrollElementIntoView(element);
 	}
+
+	public void addSelectionListener (
+			nsISelectionListener selectionListener) {
+		nsISelection selection = getSelection();
+		nsISelectionPrivate selectionPrivate = (nsISelectionPrivate) selection.queryInterface(nsISelectionPrivate.NS_ISELECTIONPRIVATE_IID);
+		selectionPrivate.addSelectionListener(selectionListener);
+		this.selectionListener = selectionListener;
+	}
+	
 }