With the new folders UI, both when browsing in the sidebar and choosing a folder for a chat, I'm not sure how the folders are currently ordered, but is isn't intuitive to me. I think maybe it's by recency?
I think sorting alphabetically is a more sensible default. However, I'm sure others would have different preferences (I know the new Assistant UI has been a bit of a flashpoint, and I also know that a big part of this was to refactor under the hood to allow for building a more robust UI for this). Perhaps it would make sense to have this be configurable (along with a great many other things about folders and the Assistant UI I assume you all are working to make configurable)?