bug 257806: handle comments in the Validator

Signed-off-by: Florian Thienel <florian@thienel.org>
diff --git a/org.eclipse.vex.core/src/org/eclipse/vex/core/internal/validator/WTPVEXValidator.java b/org.eclipse.vex.core/src/org/eclipse/vex/core/internal/validator/WTPVEXValidator.java
index f0b9f6c..8b9c0ae 100644
--- a/org.eclipse.vex.core/src/org/eclipse/vex/core/internal/validator/WTPVEXValidator.java
+++ b/org.eclipse.vex.core/src/org/eclipse/vex/core/internal/validator/WTPVEXValidator.java
@@ -25,6 +25,7 @@
 
 import org.eclipse.core.runtime.QualifiedName;
 import org.eclipse.vex.core.internal.dom.Attribute;
+import org.eclipse.vex.core.internal.dom.CommentElement;
 import org.eclipse.vex.core.internal.dom.DocumentContentModel;
 import org.eclipse.vex.core.internal.dom.Element;
 import org.eclipse.vex.core.internal.dom.Validator;
@@ -50,7 +51,10 @@
 		@Override
 		public boolean isPCData(final Object o) {
 			return "#PCDATA".equals(o);
-		};
+		}
+		public boolean isIgnorable(Object o) {
+			return CommentElement.ELEMENT_NAME.toString().equals(o);
+		}
 	};
 
 	private final DocumentContentModel documentContentModel;