diff --git a/source/java/org/alfresco/web/app/servlet/FacesHelper.java b/source/java/org/alfresco/web/app/servlet/FacesHelper.java
index 1cc7326c42..297525162f 100644
--- a/source/java/org/alfresco/web/app/servlet/FacesHelper.java
+++ b/source/java/org/alfresco/web/app/servlet/FacesHelper.java
@@ -24,6 +24,8 @@
  */
 package org.alfresco.web.app.servlet;
 
+import java.util.regex.Pattern;
+
 import javax.faces.FactoryFinder;
 import javax.faces.component.UIComponent;
 import javax.faces.component.UIViewRoot;
@@ -51,6 +53,7 @@ import org.apache.commons.logging.LogFactory;
 public final class FacesHelper
 {
    private static Log logger = LogFactory.getLog(FacesHelper.class);
+   private static Pattern FACES_ID_PATTERN = Pattern.compile("[^a-z^A-Z^_]?[^a-z^A-Z^_^-]");
    
    /**
     * Private constructor
@@ -167,14 +170,7 @@ public final class FacesHelper
    {
       if (id != null)
       {
-         // replace illegal ID characters with an underscore
-         id = id.replace(':', '_');
-         id = id.replace(' ', '_');
-         id = id.replace('.', '_');
-         id = id.replace('+', '_');
-         
-         // TODO: check all other illegal characters - only allowed dash and underscore
-         // TODO: use regular expression to do check and replacment of characters
+         id = FACES_ID_PATTERN.matcher(id).replaceAll("_");
       }
       
       return id;
diff --git a/source/java/org/alfresco/web/ui/repo/component/UIWorkflowHistory.java b/source/java/org/alfresco/web/ui/repo/component/UIWorkflowHistory.java
index 863e60f024..1bddb2d06f 100644
--- a/source/java/org/alfresco/web/ui/repo/component/UIWorkflowHistory.java
+++ b/source/java/org/alfresco/web/ui/repo/component/UIWorkflowHistory.java
@@ -201,7 +201,7 @@ public class UIWorkflowHistory extends SelfRenderingComponent
                out.write("</td><td>");
                out.write(Utils.getDateTimeFormat(context).format(createdDate));
                out.write("</td><td>");
-               out.write(owner);
+               out.write(owner == null ? "" : owner);
                out.write("</td><td>");
                out.write(comment == null ? "" : comment);
                out.write("</td><td>");