@tycho1974 I believe what @“firstname.lastname@example.org” is asking is when will the collections behave like the web app and others. In other words, it would be nice to see one thumbnail appear for the collection of movies instead of all the movies scattered throughout the library in all their non-chronological glory. Not to mention it is annoying to sort by collections the way you suggest. Yes, it is possible, but not what we Roku users are wanting.
What you’re referring to is a “playlist”, not a “collection”. A playlist is a collection of movies, episodes, or music that you can sort manually as you see fit, and a collection is basically a user-made genre. I’ve never had an issue viewing playlists on my Roku. To wit, here’s a screenshot of playlists on the web UI:
…and this is the playlist button on the Roku UI:
(Clicking that button leads you to a screen with thumbnails for the playlists, just like in the web UI)
I’ve never seen a thumbnail for collections in any UI I’ve used, but maybe I’m wrong and I don’t understand OP’s question at all.