Test in clean and boost. Go to participants page as a teacher. Select all users. Choose send a message from the bulk actions at the bottom of the page. Verify there are no options to continue searching, the function of the page is clear and the primary action is "Send message". Type a message and send it. Login as one of those users and verify they received the message. Login as a student. go to the participants page for a course. Verify you cannot do any "bulk actions". Login as a teacher again. go to the participants page. Select 3 users and choose "Add a note" from the bulk actions at the bottom of the page. Verify you see a popup with an area to type the note. Save the note and view the profile of one of the users. You should see  the note has been added. Select 3 users who have a manual enrolment.  Choose "Edit selected user enrolments" from the bulk actions at the bottom of the page. Change the enrolment status to "Suspended". Submit the form and you should go back to the participants page. The users should now be suspended.  Go to the course participation report (go to the course home page, choose "More..." from the cog and find course participation under "Reports". Change the search criteria to get some records displaying. Select some records and then select "Send a message" from the "With selected users" select box at the bottom of the page. Send a message to these users and verify they received it.