I'm finding it nearly impossible to create a component. Once I've selected sketch (rectangle, two points) or Box, the cursor shows "select first point" as it should. Hoever, as I move my cursor toward the point I'd like to select, it selects a random point along that path. So the only way for me to add anything is to create geometry at a random point in space, then move it in three dimensions to where I want it. Ouch!
I tried changing mouses and that appears to have solved my problem. I was using Apple's "magic" bluetooth mouse when the issues occured. I'm suing a Microsoft bluetooth mouse now and the issue seems to have been solved.