Unfortunately, from what it seems, the software wasn't designed to be controlled by shortcut keys. Also, the only way to delete or insert something in the playlist is to stop the playback. This is how it has been designed and in order to change that, you will need to contact the developers and ask for these functions in the next versions of the utility. You can get in touch with them using
firstname.lastname@example.org email address or
1 (250) 658-6319 phone number.