When a notification has actions, Notify OSD's fallback alert has a "Cancel" button to let you dismiss the notification without triggering any of the actions.
When a notification has no actions but has indefinite duration, Notify OSD's fallback alert still has a "Cancel" button alongside its "OK" button. This doesn't seem to be necessary; "Cancel" and "OK" do the same thing. Just an "OK" button would be enough.
notify-osd 0.9.35+ 13.10.20130917. 1-0ubuntu1, Ubuntu 13.10
When a notification has actions, Notify OSD's fallback alert has a "Cancel" button to let you dismiss the notification without triggering any of the actions.
When a notification has no actions but has indefinite duration, Notify OSD's fallback alert still has a "Cancel" button alongside its "OK" button. This doesn't seem to be necessary; "Cancel" and "OK" do the same thing. Just an "OK" button would be enough.