I saw that there was a recent patch in the GUI to add "ok/cancel"
buttons to the settings dialogue. I am going to rename them to "save
settings/close". A basic UI design principle is that a button should
say what it will do, and "ok/cancel" is not informative without
context.
I don't think "Close" is a good label here unless the settings are actually immediately saved when they are adjusted (a paradigm I personally detest for settings dialogs, but anyway). I think most people think of the "Cancel" button in a settings panel as "Cancel my changes and close". Usually the window manager should provides bare "Close" functionality. So I would either have a "Save" / "Cancel" button pair or instead just a single "Save settings" button (bonus points if it toggles activity based on whether modifications have been made). Or possibly a "Save settings" / "Undo changes" pair. I'm indifferent about "Save" vs "Save settings".