Index: src/main/java/com/xpn/xwiki/web/EditForm.java
===================================================================
--- src/main/java/com/xpn/xwiki/web/EditForm.java	(revision 10137)
+++ src/main/java/com/xpn/xwiki/web/EditForm.java	(working copy)
@@ -82,7 +82,7 @@
     public void setTags(String[] parameter)
     {
         if (parameter == null) {
-            this.tags = "";
+            this.tags = null;
             return;
         }
         StringBuffer tags = new StringBuffer();