It's probably a technique thing, but after experimenting I can't see any rhyme nor reason, so what's the "trick"?
Situation: Destination folders have been created and sit on the desktop.
In either (a) downloading data files from Gov. website, Save.....dialogue box opens inviting me to select where to Save;
or (b) creating new file in any application, Save.....dialogue box opens inviting me to select where to Save.
All OK so far.
What happens next: Sometimes the destination folder shows in the drop-down menu. Sometimes it does not, forcing the user to Save to Desktop and then drag it into the correct folder afterwards.
It makes no difference if the destination folder is already open or not. It makes no difference if one had already opened-then-closed the destination folder, in an attempt to make it show up on "Recent Places". It makes no difference which Mac out of the 4 here.
I don't get it, it's time-wasting, and I can only think I'm missing some technique.