QuoteBut I often have found that after one editing session I can no longed select anything at all in edit mode even trying the mentioned workarounds.
I think you're right, as mentioned, recreating the pop fixes the selection - tried it last night and I could edit the population easily - no need to hunt for a workable camera angle or clipping planes etc.
In this case, the population was already set up and established, so it wasn't too much hassle in the end - not tested but maybe saving the scene removes the ability to edit?
I remember doing this in TG3, so if it's a bug it's been around for a while.