This pfr box client behaviour first appeared a few weeks ago. It's the same on all my Mac devices.
There's no zoom in and out buttons. Maybe they are hidden under the Aircraft List?
There's an Aircraft List that is fixed to the RH third of the map screen. There's a swipe handle to grab the Aircraft List but it will only expand the list further on to the screen - not off.
I hope someone can help.
PFR Product ID: PFR v03
PFR Client version 5.0.152 armhf
MacOS Big Sur 11.2.3 with Safari 14.0.3
MacOS High Sierra 10.13.6 with Safari 13.1.2
iPhone and iPad iOS 14.4.1