diff --git a/content/xul/document/src/nsXULCommandDispatcher.cpp b/content/xul/document/src/nsXULCommandDispatcher.cpp
index f2ce3d1ae7b7..af6d011185f8 100644
--- a/content/xul/document/src/nsXULCommandDispatcher.cpp
+++ b/content/xul/document/src/nsXULCommandDispatcher.cpp
@@ -507,7 +507,7 @@ nsXULCommandDispatcher::Matches(const nsString& aList,
     if (aList.Equals(NS_LITERAL_STRING("*")))
         return PR_TRUE; // match _everything_!
 
-    PRInt32 indx = aList.Find(nsPromiseFlatString(aElement));
+    PRInt32 indx = aList.Find((const PRUnichar *)nsPromiseFlatString(aElement));
     if (indx == -1)
         return PR_FALSE; // not in the list at all
 
diff --git a/rdf/content/src/nsXULCommandDispatcher.cpp b/rdf/content/src/nsXULCommandDispatcher.cpp
index f2ce3d1ae7b7..af6d011185f8 100644
--- a/rdf/content/src/nsXULCommandDispatcher.cpp
+++ b/rdf/content/src/nsXULCommandDispatcher.cpp
@@ -507,7 +507,7 @@ nsXULCommandDispatcher::Matches(const nsString& aList,
     if (aList.Equals(NS_LITERAL_STRING("*")))
         return PR_TRUE; // match _everything_!
 
-    PRInt32 indx = aList.Find(nsPromiseFlatString(aElement));
+    PRInt32 indx = aList.Find((const PRUnichar *)nsPromiseFlatString(aElement));
     if (indx == -1)
         return PR_FALSE; // not in the list at all