This one is by design (at least for now). We intentionally block this because the filesapp will try to download the entire content for every file and generate a thumbnail on the client side, which is obviously extremely expensive for a network file share.

There's quite a few things that would have to change to make this possible, including better invalidation/co-ordination with the FSP to invlidate requests when the item goes off the screen before a download even starts. Right now a fling scroll in a folder full of large images would block up the work queue with redundant work.

We might also be able to get a hint from the files app so that we can put these in a low priority queue.

For now we have no current plans to do this, and also the non-windows file managers also do this.

I'm going to put this to a feature, and remove the milestone.