MDL-17361 Problems with the question category editing forms.

When editing an existing category, the logic should have been to prevent you from moving the category if it was the last remaining top-level category in its context.

When creating a new category as part of creating a random question, there should be no restriction.

question/category_form.php

@@ -16,11 +16,15 @@ function definition() {
         $questioncategoryel = $mform->addElement('questioncategory', 'parent', get_string('parent', 'quiz'),
                     array('contexts'=>$contexts, 'top'=>true, 'currentcat'=>$currentcat, 'nochildrenof'=>$currentcat));
         $mform->setType('parent', PARAM_SEQUENCE);
+        // This next test is actually looking to see if $currentcat is the id of
+        // a category that already exists, and is the only top-level category in
+        // it context. If so, we stop it from being moved.
         if (1 == $DB->count_records_sql("SELECT count(*)
                                            FROM {question_categories} c1,
                                                 {question_categories} c2
                                           WHERE c2.id = ?
-                                            AND c1.contextid = c2.contextid", array($currentcat))){
+                                            AND c1.contextid = c2.contextid
+                                            AND c1.parent = 0 AND c2.parent = 0", array($currentcat))){
             $mform->hardFreeze('parent');
         }
         $mform->setHelpButton('parent', array('categoryparent', get_string('parent', 'quiz'), 'question'));

question/category_form_randomquestion.php

@@ -16,16 +16,6 @@ function definition() {
         $questioncategoryel = $mform->addElement('questioncategory', 'parent', get_string('parentcategory', 'quiz'),
                     array('contexts'=>$contexts, 'top'=>true, 'currentcat'=>$currentcat, 'nochildrenof'=>$currentcat));
         $mform->setType('parent', PARAM_SEQUENCE);
-        if (1 == $DB->count_records_sql("SELECT count(*)
-                                           FROM {question_categories} c1,
-                                                {question_categories} c2
-                                          WHERE c2.id = ?
-                                            AND c1.contextid = c2.contextid", array($currentcat))){
-            //TODO: Tim? why does the above evaluate true, breaking the form?
-            // and more importantly, if this is a valid situation, how should we react,
-            // that is, what does this mean?
-            //$mform->hardFreeze('parent');
-        }
         $mform->setHelpButton('parent', array('categoryparent', get_string('parent', 'quiz'), 'question'));
 
         $mform->addElement('text','name', get_string('name'),'maxlength="254" size="50"');