In my modeling environment, working with imported dwg files is integral to my work flow. I primarily use these files for reference, which saves significant time. For those of us who use parametric based extensions (Profile Builder, PlusSpec, MODELLUR, Medeek etc.), connecting geometry is required to establish extension functionality. In this video (extreme magnification) the inappropriate snap points are highlighted. It is extremely difficult to snap to the bottom plate and not the dwg in this example. If the dwg is selected by mistake, the extension’s components do not function. Hope this helps in understanding the issue. The second image highlights the result of snapping to the dwg, which in this case caused the extension to perform incorrectly.