Confusing UX when opening a document with no saved data and no peers to fetch from

[adamwiggins]

I'm often confused when opening a URL with no data attached. Steps to reproduce:

1. Open a Trellis URL (say, trellis://gray-istanbul-10) without any a local copy (~/Documents/Trellis/gray-instanbul-10.trellis) or any peers who can send me the document. Best way to do this is just make something up, i.e. trellis://not-a-document

What I got: the app appears to open it, but it's a blank screen that just looks broken.

What I expected: some feedback that I have no data for this document. Effectively it is an invalid URL until I can connect to someone with a copy.