From 077edd303836b990b7badf8e9a72015451177ae5 Mon Sep 17 00:00:00 2001
From: Marina Glancy <marina@moodle.com>
Date: Tue, 21 Nov 2017 15:19:44 +0800
Subject: [PATCH] MDL-56864 forms: allow to remove last tag with forced
 standard tags

---
 lib/form/tags.php | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/form/tags.php b/lib/form/tags.php
index 390c723ed58..ef3719f9433 100644
--- a/lib/form/tags.php
+++ b/lib/form/tags.php
@@ -244,7 +244,11 @@ class MoodleQuickForm_tags extends MoodleQuickForm_autocomplete {
      */
     public function exportValue(&$submitValues, $assoc = false) {
         if (!$this->is_tagging_enabled()) {
-            return $assoc ? array($this->getName() => array()) : array();
+            return $this->_prepareValue([], $assoc);
+        }
+        if ($this->_findValue($submitValues) === '_qf__force_multiselect_submission') {
+            // Nothing was selected.
+            return $this->_prepareValue([], $assoc);
         }
 
         return parent::exportValue($submitValues, $assoc);
-- 
2.11.4.GIT