If "Show activity completion conditions" is set to "No" in course settings, mod_unilabel does not show the manual completion button.
As the button is not reachable in any other way, I'd propose that mod_unilabel behaves consistent to mod_label in this case and shows the button regardless of course settings.
If "Show activity completion conditions" is set to "No" in course settings, mod_unilabel does not show the manual completion button. As the button is not reachable in any other way, I'd propose that mod_unilabel behaves consistent to mod_label in this case and shows the button regardless of course settings.