1. Choose a course and navigate to Course Administration -> Reports -> Course participation.

2. Choose any option that will display at least 1 user.

3. Click the checkbox to select all users.

4. With selected users...send a message.

You will notice that the "Send message to # people" button text displays one additional user. Sending the message will fail with no obvious error – the "Message sent to # people" confirmation dialog does not appear, and the messages will not be sent out. I've tested this on 3.9 and 4.0 (Moodle QA Testing Site).

Upon closer inspection, you will see that the "select all" checkbox is being passed as an argument along with the actual users that were selected, causing the entire process to fail.

The problem lies in report/participation/amd/src/participants.js. "[data-toggle='slave']" needs to be added to the "Selectors" constant as follows:

const Selectors ={ bulkActionSelect: "#formactionid", bulkUserSelectedCheckBoxes: "input[data-togglegroup^='participants-table'][data-toggle='slave']:checked", participantsForm: '#participantsform', };

When this addition is made, bulk messaging works as expected. In fact, "[data-toggle='slave']" is already included in user/amd/src/participants.js, where bulk messaging also works as expected.

This is my first bug report, so any guidance on how to properly address issues like these would be greatly appreciated. Thanks, everyone!