no thats pretty much the process. does it on my mac and my pc so far with every factory file, every time. i can individually select them in the model side bar on the left but all models are always highlighted on the build plate or i can deselect everything then none are highlighted of course but then i go and click on just one model in the side bar to select it then they all light up on the build tray.
i just tried something else. i made my file with a few parts on the plate. saved as a factory file. after the save i didnt even load a different file i just grabbed the same factory file i just saved, dragged and dropped it into s3d, save settings...no, it loads the file and every model is highlighted. i cant individually select.
i made a video showing pc and mac
excuse the shakey vid. kinda tough holding an iphone while clicking and typing.
https://youtu.be/BppM_nuwwhw