diff --git a/mod/assign/feedback/comments/locallib.php b/mod/assign/feedback/comments/locallib.php
index db2deae6a9c..e6c0f4af78f 100644
--- a/mod/assign/feedback/comments/locallib.php
+++ b/mod/assign/feedback/comments/locallib.php
@@ -200,7 +200,7 @@ class assign_feedback_comments extends assign_feedback_plugin {
         global $DB;
         $feedbackcomment = $this->get_feedback_comments($grade->id);
         $quickgradecomments = optional_param('quickgrade_comments_' . $userid, null, PARAM_RAW);
-        if (!$quickgradecomments) {
+        if (!$quickgradecomments && $quickgradecomments !== '') {
             return true;
         }
         if ($feedbackcomment) {
diff --git a/mod/assign/feedback/comments/tests/behat/feedback_comments.feature b/mod/assign/feedback/comments/tests/behat/feedback_comments.feature
new file mode 100644
index 00000000000..245e53ad0c1
--- /dev/null
+++ b/mod/assign/feedback/comments/tests/behat/feedback_comments.feature
@@ -0,0 +1,47 @@
+@mod @mod_assign @assignfeedback @assignfeedback_comments
+Feature: In an assignment, teachers can provide feedback comments on student submissions
+  In order to provide feedback to students on their assignments
+  As a teacher,
+  I need to create feedback comments against their submissions.
+
+  Background:
+    Given the following "courses" exist:
+      | fullname | shortname | category | groupmode |
+      | Course 1 | C1 | 0 | 0 |
+    And the following "users" exist:
+      | username | firstname | lastname | email |
+      | teacher1 | Teacher | 1 | teacher1@example.com |
+      | student1 | Student | 1 | student1@example.com |
+    And the following "course enrolments" exist:
+      | user | course | role |
+      | teacher1 | C1 | teacher |
+      | student1 | C1 | student |
+
+  @javascript
+  Scenario: Teachers should be able to add and remove feedback comments via the quick grading interface
+    Given the following "activities" exist:
+      | activity | course | idnumber | name             | assignsubmission_onlinetext_enabled | assignfeedback_comments_enabled |
+      | assign   | C1     | assign1  | Test assignment1 | 1                                   | 1                               |
+    And I log in as "student1"
+    And I am on "Course 1" course homepage
+    And I follow "Test assignment1"
+    And I press "Add submission"
+    And I set the following fields to these values:
+      | Online text | I'm the student1 submission |
+    And I press "Save changes"
+    And I log out
+    And I log in as "teacher1"
+    And I am on "Course 1" course homepage
+    And I follow "Test assignment1"
+    And I navigate to "View all submissions" in current page administration
+    Then I click on "Quick grading" "checkbox"
+    And I set the field "Feedback comments" to "Feedback from teacher."
+    And I press "Save all quick grading changes"
+    And I should see "The grade changes were saved"
+    And I press "Continue"
+    And I should see "Feedback from teacher."
+    And I set the field "Feedback comments" to ""
+    And I press "Save all quick grading changes"
+    And I should see "The grade changes were saved"
+    And I press "Continue"
+    And I should not see "Feedback from teacher."