Index: src/org/jboss/tools/common/meta/constraint/impl/XAttributeConstraintInt.java
===================================================================
--- src/org/jboss/tools/common/meta/constraint/impl/XAttributeConstraintInt.java	(revision 22035)
+++ src/org/jboss/tools/common/meta/constraint/impl/XAttributeConstraintInt.java	(working copy)
@@ -14,7 +14,7 @@
 import org.w3c.dom.*;
 
 public class XAttributeConstraintInt extends XAttributeConstraintProperties {
-    protected boolean mandatory = true;
+    protected boolean mandatory = false;
     protected int min = Integer.MIN_VALUE;
     protected int max = Integer.MAX_VALUE;
     public XAttributeConstraintInt() {
@@ -23,7 +23,7 @@
 
     public void load(Element element) {
         super.load(element);
-        mandatory = getBoolean("mandatory", true); //$NON-NLS-1$
+        mandatory = getBoolean("mandatory", false); //$NON-NLS-1$
         min = getInt("minimum", Integer.MIN_VALUE); //$NON-NLS-1$
         max = getInt("maximum", Integer.MAX_VALUE); //$NON-NLS-1$
     }
Index: src/org/jboss/tools/common/model/engines/impl/EnginesLoader.java
===================================================================
--- src/org/jboss/tools/common/model/engines/impl/EnginesLoader.java	(revision 22035)
+++ src/org/jboss/tools/common/model/engines/impl/EnginesLoader.java	(working copy)
@@ -86,11 +86,18 @@
             		c = cs[i].copy();
                     object.addChild(c);
             	} else {
-            		boolean has_id = c.getModelEntity().getAttribute(XModelObjectLoaderUtil.ATTR_ID_NAME) != null;
+            		boolean has_id = c.getModelEntity().getAttribute(XModelObjectLoaderUtil.ATTR_ID_NAME) != null
+            			|| ((XModelObjectImpl)c).hasIdAttr();
             		if(has_id) {
             			c.removeFromParent();
             			EnginesLoader.merge(c, cs[i], false);
-            			object.addChild(c);
+            			if(!object.addChild(c)) {
+            				c.set(XModelObjectImpl.DUPLICATE, "1234");
+            				object.addChild(c);
+            			}
+            			if(c.get(XModelObjectImpl.DUPLICATE) != null) {
+            				c.set(XModelObjectImpl.DUPLICATE, "");
+            			}
             		} else {
             			EnginesLoader.merge(c, cs[i], fire);
             		}
Index: src/org/jboss/tools/common/model/markers/ConstraintChecker.java
===================================================================
--- src/org/jboss/tools/common/model/markers/ConstraintChecker.java	(revision 22035)
+++ src/org/jboss/tools/common/model/markers/ConstraintChecker.java	(working copy)
@@ -39,12 +39,19 @@
 	
 	private void check(XModelObject o) {
 		XAttribute[] as = o.getModelEntity().getAttributes();
+		String idAttr = null;
 		for (int i = 0; i < as.length; i++) {
 			String error = as[i].getConstraint().getError(o.getAttributeValue(as[i].getName()));
 			if(error != null) addProblem(o, as[i].getName(), "Value " + error);
+			if("true".equals(as[i].getProperty("id"))) idAttr = as[i].getName();
 		}
 		XModelObject[] cs = ((XModelObjectImpl)o).getLoadedChildren();
 		for (int i = 0; i < cs.length; i++) check(cs[i]);
+
+		String duplicate = o.get(XModelObjectImpl.DUPLICATE);
+		if(duplicate != null && duplicate.length() > 0 && idAttr != null) {
+			addProblem(o, idAttr, "Value " + o.getAttributeValue(idAttr) + " is not unique.");
+		}
 	}
 
 	protected void addProblem(XModelObject o, String attr, String msg) {
Index: src/org/jboss/tools/common/model/markers/ResourceMarkers.java
===================================================================
--- src/org/jboss/tools/common/model/markers/ResourceMarkers.java	(revision 22035)
+++ src/org/jboss/tools/common/model/markers/ResourceMarkers.java	(working copy)
@@ -30,7 +30,7 @@
 
 public class ResourceMarkers {
 	public static String TEXT_PROBLEM = "org.jboss.tools.common.model.textproblemmarker"; //$NON-NLS-1$
-	public static String CONSTRAINT_PROBLEM = "org.jboss.tools.common.model.web.ui.constraintsmarker"; //$NON-NLS-1$
+	public static String CONSTRAINT_PROBLEM = "org.jboss.tools.jst.web.ui.constraintsmarker"; //$NON-NLS-1$
 	public static String JST_WEB_PROBLEM = "org.jboss.tools.jst.web.ui.strutsmarker"; //$NON-NLS-1$
 	private XModelObject object;
 	
Index: src/org/jboss/tools/common/model/util/XModelObjectLoaderUtil.java
===================================================================
--- src/org/jboss/tools/common/model/util/XModelObjectLoaderUtil.java	(revision 22035)
+++ src/org/jboss/tools/common/model/util/XModelObjectLoaderUtil.java	(working copy)
@@ -223,9 +223,13 @@
         XModelEntity entity = o.getModelEntity();
         XAttribute[] as = entity.getAttributes();
         for (int i = 0; i < as.length; i++) {
+            String n = as[i].getName();
+            if("attributes".equals(n) && "true".equals(as[i].getProperty("any"))) { //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
+            	loadAnyAtributes(element, o);
+            	continue;
+            }
             String xmlname = as[i].getXMLName();
             if (xmlname == null || xmlname.length() == 0) continue;
-            String n = as[i].getName();
             String value = getAttribute(element, xmlname, as[i]);
             if (value != null) o.setAttributeValue(n, value);
             String commentName = getAttributeCommentName(xmlname);
@@ -332,6 +336,17 @@
             		if(q != null) EnginesLoader.merge(q, co, false);
             	} catch (XModelException exc) {
             		ModelPlugin.getPluginLog().logError("XModelObjectLoaderUtil:loadChildren:" + exc.getMessage(), exc); //$NON-NLS-1$
+        		} else {
+        			int k = 1;
+        			String pp = co.getPathPart();
+        			while(o.getChildByPath(pp) != null) {
+        				co.set(XModelObjectImpl.DUPLICATE, "" + k); //$NON-NLS-1$
+        				String ppn = co.getPathPart();
+        				if(ppn.equals(pp)) break;
+        				pp = ppn;
+        				++k;
+        			}
+        			o.addChild(co);
             	}
             	continue;
             } 
@@ -443,9 +458,13 @@
         }
         for (int i = 0; i < as.length; i++) {
             if (as[i].isFake()) continue;
+            String n = as[i].getName();
+            if("attributes".equals(n) && "true".equals(as[i].getProperty("any"))) { //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
+            	saveAnyAtributes(element, o);
+            	continue;
+            }
             String xmlname = as[i].getXMLName();
             if (xmlname == null || xmlname.length() == 0) continue;
-            String n = as[i].getName();
             String v = o.getAttributeValue(n);
             if (isSaveable(entity, n, v, as[i].getDefaultValue())) {
                 saveAttribute(element, xmlname, v);
@@ -843,6 +862,23 @@
 	
 	protected void loadAnyElement(Element element, XModelObject o) {
 		o.setAttributeValue("tag", element.getTagName()); //$NON-NLS-1$
+		loadAnyAtributes(element, o);
+		String text = getAttribute(element, "#text").trim(); //$NON-NLS-1$
+		if(text.length() > 0) {
+			while(text.startsWith("\n") || text.startsWith("\r")) text = text.substring(1); //$NON-NLS-1$ //$NON-NLS-2$
+			while(text.endsWith("\n") || text.endsWith("\r")) text = text.substring(0, text.length() - 1); //$NON-NLS-1$ //$NON-NLS-2$
+			o.setAttributeValue("text", text); //$NON-NLS-1$
+		}
+		loadChildren(element, o);
+	}
+
+	public static void loadAnyAtributes(Element element, XModelObject o) {
+		HashSet<String> attrs = new HashSet<String>();
+		XAttribute[] oas = o.getModelEntity().getAttributes();
+		for (XAttribute a: oas) {
+			String xml = a.getXMLName();
+			if(xml != null && xml.length() > 0) attrs.add(xml);
+		}
 		StringBuffer sb = new StringBuffer();
 		NamedNodeMap as = element.getAttributes();
 		for (int i = 0; i < as.getLength(); i++) {
@@ -848,6 +884,7 @@
 		for (int i = 0; i < as.getLength(); i++) {
 			Node n = as.item(i);
 			String nm = n.getNodeName();
+			if(attrs.contains(nm)) continue;
 			String v = n.getNodeValue();
 			if(v == null) continue;
 			if(sb.length() > 0) sb.append(";"); //$NON-NLS-1$
@@ -854,13 +891,6 @@
 			sb.append(nm).append("=").append(v); //$NON-NLS-1$
 		}
 		o.setAttributeValue("attributes", sb.toString()); //$NON-NLS-1$
-		String text = getAttribute(element, "#text").trim(); //$NON-NLS-1$
-		if(text.length() > 0) {
-			while(text.startsWith("\n") || text.startsWith("\r")) text = text.substring(1); //$NON-NLS-1$ //$NON-NLS-2$
-			while(text.endsWith("\n") || text.endsWith("\r")) text = text.substring(0, text.length() - 1); //$NON-NLS-1$ //$NON-NLS-2$
-			o.setAttributeValue("text", text); //$NON-NLS-1$
-		}
-		loadChildren(element, o);
 	}
     
 	protected void saveAnyElement(Element parent, XModelObject o) {
@@ -870,6 +900,18 @@
 			xmlname = namespace + ":" + xmlname; //$NON-NLS-1$
 		}
 		Element element = XMLUtil.createElement(parent, xmlname);
+		saveAnyAtributes(element, o);
+		String text = o.getAttributeValue("text"); //$NON-NLS-1$
+		if(text != null && text.length() > 0) {
+			saveAttribute(element, "#text", text); //$NON-NLS-1$
+		}
+		XModelObject[] cs = o.getChildren();
+		for (int i = 0; i < cs.length; i++) {
+			saveAnyElement(element, cs[i]);
+		}
+	}
+
+	public static void saveAnyAtributes(Element element, XModelObject o) {
 		String attrs = o.getAttributeValue("attributes"); //$NON-NLS-1$
 		StringTokenizer st = new StringTokenizer(attrs, ";"); //$NON-NLS-1$
 		while(st.hasMoreTokens()) {
@@ -880,14 +922,6 @@
 			String v = t.substring(i + 1);
 			element.setAttribute(n, v);
 		}
-		String text = o.getAttributeValue("text"); //$NON-NLS-1$
-		if(text != null && text.length() > 0) {
-			saveAttribute(element, "#text", text); //$NON-NLS-1$
-		}
-		XModelObject[] cs = o.getChildren();
-		for (int i = 0; i < cs.length; i++) {
-			saveAnyElement(element, cs[i]);
-		}
 	}
 
 	protected void eitherOr(Element element, String attr1, String attr2) {
@@ -941,6 +975,9 @@
 			}
 		}
 		mergeFinalComment(destination, source, fire);
+		
+		String d = destination.get(XModelObjectImpl.DUPLICATE);
+		if(d != null && d.length() > 0) destination.set(XModelObjectImpl.DUPLICATE, "");
 	}
 	
 	public static void mergeAttributeComment(XModelObject destination, XModelObject source, XAttribute attr, boolean fire) {
Index: src/org/jboss/tools/common/model/impl/XModelObjectImpl.java
===================================================================
--- src/org/jboss/tools/common/model/impl/XModelObjectImpl.java	(revision 22035)
+++ src/org/jboss/tools/common/model/impl/XModelObjectImpl.java	(working copy)
@@ -40,6 +40,7 @@
 public class XModelObjectImpl implements XModelObject, Serializable, Cloneable {
     private static final long serialVersionUID = 3860648580262144825L;
 //    protected static final String ENTITY = XModelConstants.XMODEL_ENTITY_ATTR;
+    public static final String DUPLICATE = "__duplicate";
     private XModel model = null;
     private XModelEntity entity = null;
     private XModelObjectImpl parent = null;
@@ -136,6 +137,21 @@
         properties.put(name.intern(), value);
     }
 
+    private Boolean hasIdAttr = null;
+    
+    public boolean hasIdAttr() {
+    	if(hasIdAttr != null) return hasIdAttr.booleanValue();
+    	hasIdAttr = Boolean.FALSE;
+    	for (int i =  0; i < getModelEntity().getAttributes().length; i++) {
+    		if("true".equals(getModelEntity().getAttributes()[i].getProperty("id"))) {
+    			hasIdAttr = Boolean.TRUE;
+    			break;
+    		}
+    	}
+    	
+    	return hasIdAttr.booleanValue();
+    }
+
     protected String get_0(String name) {
         XAttribute a = getModelEntity().getAttribute(name);
         return (a == null || a.getAdapter() == null) ? null : a.getAdapter().getProperty(this);
@@ -300,7 +316,16 @@
 
     public String getPathPart() {
         String p = name();
-        return (p == null || p.indexOf('/') < 0) ? p : p.replace('/', '#');
+        p = ((p == null || p.indexOf('/') < 0) ? p : p.replace('/', '#'));
+        return applyDuplicate(p);
+    }
+   
+    protected final String applyDuplicate(String pathpart) {
+        String duplicate = get(DUPLICATE);
+        return (duplicate == null || duplicate.length() == 0) 
+        	? pathpart 
+        	: pathpart + DUPLICATE + duplicate;
+    	
     }
 
     public XModelObject getChildByPath(String path) {
@@ -360,6 +385,10 @@
         String entity = (transform) ? getEntityForCopy() : getModelEntity().getName();
         XModelObject c = getModel().createModelObject(entity, p);
         if(c != null) c.setModified(true);
+        String d = get(DUPLICATE);
+        if(d != null && d.length() > 0) {
+        	c.set(DUPLICATE, d);
+        }
         return c;
     }
 
Index: src/org/jboss/tools/common/model/impl/RegularObjectImpl.java
===================================================================
--- src/org/jboss/tools/common/model/impl/RegularObjectImpl.java	(revision 22035)
+++ src/org/jboss/tools/common/model/impl/RegularObjectImpl.java	(working copy)
@@ -117,6 +117,18 @@
         			k++;
         		}
         		return;
+        	} else if(hasIdAttr()) {
+        		int k = 1;
+        		while(c != null) {
+        			super.set(XModelObjectImpl.DUPLICATE, "" + k); //$NON-NLS-1$
+        			npp = getPathPart();
+        			if(k == 1 && npp.indexOf(XModelObjectImpl.DUPLICATE) < 0) {
+        				elementExists(c, name, value);
+        				return;
+        			}
+        			c = p.children.change(this, opp, npp);
+        			k++;
+        		}
         	} else {
         		if(ov == null) properties.remove(name); else super.set(name, ov);
         		elementExists(c, name, value);