Index: src/org/teiid/designer/extension/ui/editors/ModelExtensionDefinitionEditor.java
===================================================================
--- src/org/teiid/designer/extension/ui/editors/ModelExtensionDefinitionEditor.java	(revision 2129)
+++ src/org/teiid/designer/extension/ui/editors/ModelExtensionDefinitionEditor.java	(working copy)
@@ -54,7 +54,6 @@
 import org.eclipse.ui.PartInitException;
 import org.eclipse.ui.dialogs.SaveAsDialog;
 import org.eclipse.ui.editors.text.FileDocumentProvider;
-import org.eclipse.ui.editors.text.TextEditor;
 import org.eclipse.ui.forms.IManagedForm;
 import org.eclipse.ui.forms.IMessageManager;
 import org.eclipse.ui.forms.editor.FormPage;
@@ -102,8 +101,9 @@
     private ModelExtensionDefinition medBeingEdited;
 
     private MedEditorPage overviewPage;
-
     private MedEditorPage propertiesPage;
+    private MedEditorPage sourcePage;
+    
     private ScrolledForm scrolledForm;
     private final Collection<MedEditorPage> pages = new ArrayList<MedEditorPage>(2);
 
@@ -137,22 +137,12 @@
     @Override
     protected void addPages() {
         // NOTE: pages are added in reverse order
+
         try {
             // last page is a readonly text editor
-            TextEditor sourceEditor = new TextEditor() {
-                /**
-                 * {@inheritDoc}
-                 * 
-                 * @see org.eclipse.ui.texteditor.AbstractDecoratedTextEditor#isEditable()
-                 */
-                @Override
-                public boolean isEditable() {
-                    return false;
-                }
-            };
-
-            // add text editor
-            addPage(0, sourceEditor, getEditorInput());
+            this.sourcePage = new SourceEditorPage(this);
+            addPage(0, this.sourcePage);
+            this.pages.add(this.sourcePage);
 
             // add properties editor
             this.propertiesPage = new PropertiesEditorPage(this);
@@ -165,7 +155,6 @@
             this.pages.add(this.overviewPage);
 
             // set text editor title and initialize header text to first page
-            setPageText((getPageCount() - 1), Messages.medEditorSourcePageTitle);
             this.scrolledForm.setText(getPageText(0));
 
             // handle page changes
@@ -563,6 +552,7 @@
         // pass event on to pages
         this.overviewPage.handlePropertyChanged(e);
         this.propertiesPage.handlePropertyChanged(e);
+        this.sourcePage.handlePropertyChanged(e);
     }
 
     /**
@@ -655,7 +645,10 @@
             this.overviewPage.getManagedForm().refresh();
 
             this.propertiesPage.setResourceReadOnly(this.readOnly);
-            this.overviewPage.getManagedForm().refresh();
+            this.propertiesPage.getManagedForm().refresh();
+
+            this.sourcePage.setResourceReadOnly(this.readOnly);
+            this.sourcePage.getManagedForm().refresh();
         }
     }
 
Index: src/org/teiid/designer/extension/ui/editors/SourceEditorPage.java
===================================================================
--- src/org/teiid/designer/extension/ui/editors/SourceEditorPage.java	(revision 0)
+++ src/org/teiid/designer/extension/ui/editors/SourceEditorPage.java	(revision 0)
@@ -0,0 +1,106 @@
+/*
+ * JBoss, Home of Professional Open Source.
+ *
+ * See the LEGAL.txt file distributed with this work for information regarding copyright ownership and licensing.
+ *
+ * See the AUTHORS.txt file distributed with this work for a full listing of individual contributors.
+ */
+package org.teiid.designer.extension.ui.editors;
+
+import static org.teiid.designer.extension.ui.UiConstants.EditorIds.MED_SOURCE_PAGE;
+
+import java.beans.PropertyChangeEvent;
+
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.layout.GridData;
+import org.eclipse.swt.layout.GridLayout;
+import org.eclipse.swt.widgets.Composite;
+import org.eclipse.swt.widgets.Display;
+import org.eclipse.swt.widgets.Text;
+import org.eclipse.ui.forms.widgets.FormToolkit;
+import org.teiid.designer.extension.definition.ModelExtensionDefinitionWriter;
+import org.teiid.designer.extension.ui.Messages;
+
+/**
+ * 
+ */
+public class SourceEditorPage extends MedEditorPage {
+
+    private Text content;
+    private final ModelExtensionDefinitionWriter writer;
+
+    /**
+     * @param medEditor the MED editor this page belongs to (cannot be <code>null</code>)
+     */
+    protected SourceEditorPage( ModelExtensionDefinitionEditor medEditor ) {
+        super(medEditor, MED_SOURCE_PAGE, Messages.medEditorSourcePageTitle);
+        this.writer = new ModelExtensionDefinitionWriter();
+    }
+
+    /**
+     * {@inheritDoc}
+     * 
+     * @see org.teiid.designer.extension.ui.editors.MedEditorPage#createBody(org.eclipse.swt.widgets.Composite,
+     *      org.eclipse.ui.forms.widgets.FormToolkit)
+     */
+    @Override
+    protected void createBody( Composite body,
+                               FormToolkit toolkit ) {
+        body.setLayout(new GridLayout());
+        body.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
+        body.setBackground(Display.getCurrent().getSystemColor(SWT.COLOR_WIDGET_LIGHT_SHADOW));
+
+        this.content = new Text(body, SWT.READ_ONLY | SWT.MULTI | SWT.WRAP);
+        this.content.setBackground(body.getBackground());
+        setContent();
+    }
+
+    /**
+     * {@inheritDoc}
+     * 
+     * @see org.teiid.designer.extension.ui.editors.MedEditorPage#handlePropertyChanged(java.beans.PropertyChangeEvent)
+     */
+    @Override
+    protected void handlePropertyChanged( PropertyChangeEvent e ) {
+        if ((this.content != null) && !this.content.isDisposed()) {
+            // make sure UI thread
+            this.content.getDisplay().syncExec(new Runnable() {
+
+                /**
+                 * {@inheritDoc}
+                 *
+                 * @see java.lang.Runnable#run()
+                 */
+                @Override
+                public void run() {
+                    setContent();
+                }
+            });
+        }
+    }
+
+    void setContent() {
+        this.content.setText(this.writer.writeAsText(getMed()));
+    }
+
+    /**
+     * {@inheritDoc}
+     * 
+     * @see org.teiid.designer.extension.ui.editors.MedEditorPage#setResourceReadOnly(boolean)
+     */
+    @Override
+    protected void setResourceReadOnly( boolean readOnly ) {
+        // nothing to do
+    }
+
+    /**
+     * {@inheritDoc}
+     * 
+     * @see org.teiid.designer.extension.ui.editors.MedEditorPage#updateAllMessages()
+     */
+    @Override
+    protected void updateAllMessages() {
+        // nothing to do
+    }
+
+}
Index: src/org/teiid/designer/extension/ui/UiConstants.java
===================================================================
--- src/org/teiid/designer/extension/ui/UiConstants.java	(revision 2129)
+++ src/org/teiid/designer/extension/ui/UiConstants.java	(working copy)
@@ -27,6 +27,7 @@
         String MED_EDITOR = PLUGIN_ID + ".modelDefinitionEditor"; //$NON-NLS-1$
         String MED_OVERVIEW_PAGE = PLUGIN_ID + ".overviewPage"; //$NON-NLS-1$
         String MED_PROPERTIES_PAGE = PLUGIN_ID + ".propertiesPage"; //$NON-NLS-1$
+        String MED_SOURCE_PAGE = PLUGIN_ID + ".sourcePage"; //$NON-NLS-1$
     }
     
     interface ExtensionIds {