Inconsistent description between wl_data_offer.source_actions and wl_data_source.set_actions
wl_data_source.set_actions
says
This request must be made once only, and can only be made on sources used in drag-and-drop, so it must be performed before wl_data_device.start_drag.
wl_data_offer.source_actions
says
This event indicates the actions offered by the data source. It will be sent right after wl_data_device.enter, or anytime the source side changes its offered actions through wl_data_source.set_actions.