Two types of activity (HotPot and H5P) will not show the 'Mark as done' button inside or on the course page.
The activities I have in my course are set to 'Students may manually mark as complete'. The setting for the course is set to NO for Show activity completion.
I would like the button to display so as to distinguish optional activties from mandatory ones (the 'Mark as done' ones are optional, and for students to be able to keep track of which optional activities they have completed.
In fact, in Editing mode, the behaviour is strange: when toggling between Hide and Show, the buttons will appear on the course page, but then disappear when I revert to Non-editing mode (student or teacher view). Sometimes they will show when the activity is set to Hide, or else set to Show, as below. The behaviour seems unpredictable.