This is so obvious and long-requested that I won’t insult the OmniGroup developers by actually describing it.
We need it.
You need it.
You’d better send an email to OmniGroup, as that is the official way for support/feature requests.
You can find what you need in Settings>
Send Feedbackon iOS or
Help>
Contact Omni` on OS X
Thanks - I have already done this, but I probably didn’t adequately flag my messages specifically as “feature requests”, so I’ll re-send them (and a few more classic oldies) with more specific subject-lines.