I recently volunteered to do a small project as a part of my interview for the role or UI / UX Designer. I used a collapsible sections for the filters:
One of the developer on the panel said this tree menu is a 10 year old design, said he last saw it several years back in an ASP.net application and resembles the old wordpress sidebar. Is tree menu unsuitable today? Is this even a tree menu?
Here's the full mockup incase you want to check it out. They weren't impressed with my work and I didn't get the job but just thought I'd ask it out just for my satisfaction.
(P.S. In response to their question "which website have you come across lately that you absolutely love", I said "ditto.com". To which they said, its looks plain and boring and there's nothing special about it, anyone can design it. — Really? Its not mind-blowing, but its great. If I remembered at the time, I'd have said xamarin.com or stripe.com instead.)