Online version uploads file to target directory but does not start print automatically. In my local copy, fiddling with export.js by changing api call (POST) /api/files/local to /server/files/upload and simply adding a form.append("print","true") somewhere worked flawless for me.
But a checkbox of "Start Printing after Upload" similar to Cura/Slic3r/PS/SS would be an ultimate solution since online version is embeddable in OnShape, Thingiverse and some other sites. It’s a royal nuisance everytime changing the browser tab to Fluidd/Octoprint just for starting a print.
Closely related issue is persistency of host and api key (and a putative checkbox) values for both local and remote targets. These values can be stored in cookies(?) just like every other parameter.