One annoying thing is that I have to be in the title of the task to submit the form.

If the focus leaves the title onto one of the other fields e.g. duration, I have to go back to the title to be able to create the task.

There isn't even a button, though I prefer to use my keyboard as much as I can anyway.

I think ⌘+Enter should work anywhere in the form to submit it, and ESC to dismiss it.