You've absolutely nailed the Go To File functionality, and I think that's awesome. One complaint, to do with File Preview:
I primarily navigate my projects with Go To File (Cmd+T), and I don't really pay attention to the physical tabs at all. I love the ease that I can hop between two, three, or sometimes four different files by using Cmd+T, Down, and Enter.
The only time this becomes a problem is when I sometimes single-click to open a file from the sidebar. I'm aware that this triggers a Preview and not a new tab. Again, I don't mind this behavior but I would love it if this Preview'ed file would get added to the Go To File history. As it stands, if I just want to reference a file, but not edit it, there is no way to hop back and forth between the two unless I double-click the file from the sidebar to give it a proper tab.
I see two easy solutions:
1) allow single-click to "Open" a file rather than "Preview" a file in preferences
2) add Preview'ed files to the Go To File history so that I can "Go To File"-hop between them
Much appreciated, and excellent work so far.
Edit: modified option 1)