There’s absolutely no reason it should consume any CPU at all when not working. We’ve not seen that at all.
Can you please let us know more about when this happens? For example, if you exit it, restart and sign in – does it happen then?
How many (approximately) files do you have in the ‘recent files’ list?
This is by no means by design, and if we could learn more we’ll absolutely fix it as soon as possible.