The performance is quite bad. There are some basics missing or broken.
- no caching for file previews
- no sorting by date in the file picker
- no sorting by size in the file picker
- no sorting by file type in the file picker
- no search in the file picker
- cant enter a folder in the detail view (only expand) in the file picker
- cant go to page (by page number) in the document viewer
- after clicking a button in the document viewer, focus is lost on the document and arrow keys, space, pgup/pgdown dont work until the document is clicked again
- cant select text in the document viewer, unless I search first, in which case it then works
This is after looking at the file picker and document viewer less than 3 minutes(!!!). I gave up after that. Getting 80% of a file picker is easy, getting the last 20% done, so that it's on par with existing software, is not.
Very very odd to have things look this polished, yet be this terrible functionality- and performance-wise. These are not random quirky new ideas I'm having, these have been basics that work in every single file picker and document viewer since the early days of UI, before the web.