diff --git a/lib/filterlib.php b/lib/filterlib.php
index 6639534..2ecbcfa 100644
--- a/lib/filterlib.php
+++ b/lib/filterlib.php
@@ -664,14 +664,14 @@ function filter_get_active_in_context($context) {
     // The following SQL is tricky. It is explained on
     // http://docs.moodle.org/en/Development:Filter_enable/disable_by_context
     $sql = "SELECT active.filter, fc.name, fc.value
-         FROM (SELECT f.filter
+         FROM (SELECT f.filter, MAX(f.sortorder) AS max_sortorder
              FROM {filter_active} f
              JOIN {context} ctx ON f.contextid = ctx.id
              WHERE ctx.id IN ($contextids)
-             GROUP BY filter
+             GROUP BY f.filter
              HAVING MAX(f.active * " . $DB->sql_cast_2signed('ctx.depth') .
                     ") > -MIN(f.active * " . $DB->sql_cast_2signed('ctx.depth') . ")
-             ORDER BY MAX(f.sortorder)) active
+             ORDER BY max_sortorder) active
          LEFT JOIN {filter_config} fc ON fc.filter = active.filter AND fc.contextid = $context->id";
     $rs = $DB->get_recordset_sql($sql);
 
@@ -718,7 +718,7 @@ function filter_get_available_in_context($context) {
                 CASE WHEN fa.active IS NULL THEN " . TEXTFILTER_INHERIT . "
                 ELSE fa.active END AS localstate,
              parent_states.inheritedstate
-         FROM (SELECT f.filter,
+         FROM (SELECT f.filter, MAX(f.sortorder) AS max_sortorder
                     CASE WHEN MAX(f.active * " . $DB->sql_cast_2signed('ctx.depth') .
                             ") > -MIN(f.active * " . $DB->sql_cast_2signed('ctx.depth') . ") THEN " . TEXTFILTER_ON . "
                     ELSE " . TEXTFILTER_OFF . " END AS inheritedstate
@@ -727,7 +727,7 @@ function filter_get_available_in_context($context) {
              WHERE ctx.id IN ($contextids)
              GROUP BY f.filter
              HAVING MIN(f.active) > " . TEXTFILTER_DISABLED . "
-             ORDER BY MAX(f.sortorder)) parent_states
+             ORDER BY max_sortorder) parent_states
          LEFT JOIN {filter_active} fa ON fa.filter = parent_states.filter AND fa.contextid = $context->id";
     return $DB->get_records_sql($sql);
 }