Fix sorting

src/biber/filter.xml

@@ -37,10 +37,10 @@
                 <map_step map_field_source="homepage"/>
                 <map_step map_field_set="userd" map_origfieldval="1"/>
             </map>
-            <map map_overwrite="1">
-                <map_step map_field_set="sortkey" map_field_value="D"/>
+            <map map_overwrite="0">
                 <map_step map_field_source="core"/>
-                <map_step map_field_set="sortkey" map_origfieldval="1"/>
+                <map_step map_field_set="sortkey" map_origfieldval="1" map_final="1"/>
+                <map_step map_field_set="sortkey" map_field_value="D"/>
             </map>
         </maps>
     </sourcemap>
@@ -48,10 +48,7 @@
         <sort order="1" sort_direction="descending">
             <sortitem order="1" >year</sortitem>
         </sort>
-        <!--<sort order="2" sort_direction="ascending" final="1">
-            <sortitem order="1">userc</sortitem>
-        </sort>-->
-        <sort order="3" sort_direction="ascending" final="1">
+        <sort order="2" sort_direction="ascending">
             <sortitem order="1">sortkey</sortitem>
         </sort>
     </sortingtemplate>