diff --git a/mozilla/mailnews/base/search/src/nsMsgFilter.cpp b/mozilla/mailnews/base/search/src/nsMsgFilter.cpp
index 6fb124567f8..133d4c1a734 100644
--- a/mozilla/mailnews/base/search/src/nsMsgFilter.cpp
+++ b/mozilla/mailnews/base/search/src/nsMsgFilter.cpp
@@ -406,8 +406,7 @@ NS_IMETHODIMP nsMsgFilter::GetTerm(PRInt32 termIndex,
       term->GetValue(value);
     if(booleanAnd)
       term->GetBooleanAnd(booleanAnd);
-    if (attrib && !arbitraryHeader.IsEmpty() 
-        && *attrib > nsMsgSearchAttrib::OtherHeader 
+    if (attrib && *attrib > nsMsgSearchAttrib::OtherHeader 
         && *attrib < nsMsgSearchAttrib::kNumMsgSearchAttributes)
       term->GetArbitraryHeader(arbitraryHeader);
   }
diff --git a/mozilla/mailnews/base/search/src/nsMsgFilterList.cpp b/mozilla/mailnews/base/search/src/nsMsgFilterList.cpp
index 6bc1ad8e650..43a1a5b113c 100644
--- a/mozilla/mailnews/base/search/src/nsMsgFilterList.cpp
+++ b/mozilla/mailnews/base/search/src/nsMsgFilterList.cpp
@@ -1171,7 +1171,7 @@ nsresult nsMsgFilterList::ComputeArbitraryHeaders()
           {
             if (m_arbitraryHeaders.IsEmpty())
               m_arbitraryHeaders.Assign(arbitraryHeader);
-            else if (PL_strncasecmp(m_arbitraryHeaders.get(), arbitraryHeader.get(), arbitraryHeader.Length()))
+            else if (m_arbitraryHeaders.Find(arbitraryHeader, PR_TRUE) == kNotFound)
             {
               m_arbitraryHeaders.Append(" ");
               m_arbitraryHeaders.Append(arbitraryHeader);