Fix SeaMonkey bustage from bug 325842. looks reasonable from Neil over irc.

xpfe/components/autocomplete/resources/content/autocomplete.xml

@@ -158,6 +158,10 @@
                 onset="this.setAttribute('autofillaftermatch', val); return val;"
                 onget="return this.getAttribute('autofillaftermatch') == 'true';"/>
 
+      <property name="completeDefaultIndex"
+                onset="this.setAttribute('completedefaultindex', val); return val;"
+                onget="return this.getAttribute('completedefaultindex') == 'true';"/>
+
       <!--  if this attribute is set, allow different style for 
             non auto-completed lines -->
       <property name="highlightNonMatches"
@@ -1118,7 +1122,8 @@
               this.mDefaultMatchFilled)
             return;
 
-          if (!this.mFinishAfterSearch && this.autoFill && 
+          if (!this.mFinishAfterSearch &&
+              (this.autoFill || this.completeDefaultIndex) && 
               this.mLastKeyCode != KeyEvent.DOM_VK_BACK_SPACE &&
               this.mLastKeyCode != KeyEvent.DOM_VK_DELETE) {
             var indexToUse = aResults.defaultItemIndex;
@@ -1135,7 +1140,7 @@
                 this.setTextValue(this.value + resultValue.substr(endPoint));
                 this.mInputElt.setSelectionRange(endPoint, this.value.length);
               } else {
-                if (this.autoFillAfterMatch) {
+                if (this.autoFillAfterMatch || this.completeDefaultIndex) {
                   this.setTextValue(this.value + " >> " + resultValue);
                   this.mInputElt.setSelectionRange(entry.length, this.value.length);
                 } else {