when I want to load an existing notebook and click on ".." or "[top]" I get a list of the (alphabetically) first 50 Collabs. I cannot select any Collab beyond those since a search function or "load more" is not visible.
I would also suggest that only folders and files with .ipynb extension are shown. Clicking on other files directly gives a ContentTypeError.
Besides, I think that it is a bit misleading (and potentially dangerous) that loading a notebook to a Collab does not mean to create a copy of an existing one, but actually allows to modify the original one from (another) Collab.