Thanks Jo for getting back. Yes, I've started the population over again and now have a better sense of where I need to create the population. Another thing I noticed when using the eraser was that that the object 'bounding boxes' would still appear on the erased areas after re-populating. In fact, there were still traces of the objects-erased areas after applying the erasure.
I guess being more careful when painting is the key to avoid problems. The mask applied when starting the painter would be great if it were 'somewhat lighter' so you could better see the terrain details (or, a larger preview). For now, in any event, I'm glad to get back to this image and look forward to completing it.
Thanks again for your help.
Bob