diff --git a/bundles/org.eclipse.jst.jsp.core/src/org/eclipse/jst/jsp/core/taglib/TaglibIndex.java b/bundles/org.eclipse.jst.jsp.core/src/org/eclipse/jst/jsp/core/taglib/TaglibIndex.java
index 722b7e2..d4d15cc 100644
--- a/bundles/org.eclipse.jst.jsp.core/src/org/eclipse/jst/jsp/core/taglib/TaglibIndex.java
+++ b/bundles/org.eclipse.jst.jsp.core/src/org/eclipse/jst/jsp/core/taglib/TaglibIndex.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2005, 2013 IBM Corporation and others.
+ * Copyright (c) 2005, 2014 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -773,12 +773,20 @@
 		return fCurrentTopLevelDelta;
 	}
 
-	synchronized void fireCurrentDelta(Object trigger) {
-		if (fCurrentTopLevelDelta != null) {
-			fCurrentTopLevelDelta.trigger = trigger;
-			ITaglibIndexDelta delta = fCurrentTopLevelDelta;
-			fCurrentTopLevelDelta = null;
-			fireTaglibDelta(delta);
+	void fireCurrentDelta(Object trigger) {
+		LOCK.acquire();
+		try {
+			synchronized (this) {
+				if (fCurrentTopLevelDelta != null) {
+					fCurrentTopLevelDelta.trigger = trigger;
+					ITaglibIndexDelta delta = fCurrentTopLevelDelta;
+					fCurrentTopLevelDelta = null;
+					fireTaglibDelta(delta);
+				}
+			}
+		}
+		finally {
+			LOCK.release();
 		}
 	}