How can I turn off the beeping warning bell

I just got the new Omnioutliner Pro 5 for mac, and for the most part it’s been an overall positive experience (I love the solarized dark theme). However there’s a major annoyance that’s threatening to make the software unusable for me: the program emits an alarm beep when you try to move the cursor out of bounds with the arrow keys. The needless beep, combined with the fact that there’s no obvious way to turn it off, is just super distracting and definitely one of my biggest pet peeves in terms of professional software.

I realize that not everyone may be as annoyed by the beeping as I am, but I bet at least some people are, and there needs to be a way to turn it off. The beeping is a completely pointless feature that accomplishes nothing. For example, the text box that I’m typing in right now does not beep on cursor-out-of-bounds, and yet somehow it’s perfectly functional. Other programs that have a similar beep, such as Apple Terminal and iTerm2, at the very least have a checkbox option for enabling/disabling it.

Does anyone actually know how to disable the warning beep, or, if not, what the best way is to convince the Omni Devs to add a “play alert” checkbox?