The funniest authors draw ships with the sails unfurled while the ships are anchored or moored.
Funny enough there are circumstances when you actually do that...
Wind conditions must be right, of course, but it's a good and efficient way to inspect the sails, do minor repairs, and generally checking up on stuff
without having to take them down to the deck.
Only so much room on a ship, re-rigging a sail is a
major effort, and some jobs are simply easier when a sail is hanging down.
Another reason to do it is to keep the ship aligned to the wind (and the waves....) at anchor.
You do, of course, never use full sail, but there's 16th to 18th C paintings aplenty where you can actually
see ships docked in harbour with some sails unfurled.
Some even portray the other effect of those wind conditions: Some sails unfurled, usually reefed, with the sloops out a-rowing to get a ship in far enough to toss/row out a rope and haul it to dock..
(living in a city which has retained its original medieval harbours/docks gives you a lot of "useless" knowledge in a "how did they do it" sense if you're willing to Look and Listen...)
Incidentally, despite what's shown here, those large ships rarely if ever were moored like you see here. The harbours simply weren't built for it.
They stayed out at anchor in open water in the middle of the harbour or right in front of it, and smaller ships, rowed or sailed, serviced/loaded/unloaded them.
There were specific guilds for exactly that purpose in medieval times, which had their successors well into the 19th C.