Mechanism to open files
Are we talking open(upload) through the browser? Do you want to open via web-socket or http? I had to hack together a tornado app a while ago that needed to upload text and excel files via websocket, it took a long time to figure out.
That's a good question. I think we should distinguish between a desktop solution where the server can provide a view on the user's file-system, and a web-solution for uploading files. Though maybe the latter is enough.
In #550 I added an experimental FileBrowserWidget, which might be a basis for loading files for desktop apps.