I'm in the dialogue to create a new physical volume. That part of the UI basically work: I can create PV's. What puzzles me is that the UI offers existing logical volumes to create a PV on it (see screen shot). I'm not sure if it is possible to create a PV on top of an LV, but at least it doesn't make sense to do so.
I suggest to build a filter: LV's should not be selectable in this dialogue.
P.S.: don't wonder about the sizes of the volumes, this is just a VM for OMV4 beta testing.