I methodically tried every visible menu and sub-menu and found none of the items you mentioned. Mine is version 8.
I use the term 'placement' when choosing a precise point at which to start or stop a Pencil line. I also use the term 'placement' when referring to the precise point at which I release the left mouse button after dragging an object to a new location. It has been my experience with SU that the little boxes are only kidding when they open to say things like 'Edge' or 'Endpoint'. On my computer, what they really mean is that I am close. Every line drawn requires a magnified view of each connection point to forge a closing of the gap. This, of course, typically results in coplaner nightmares.
As to scale, nothing larger than a house plan, but my work includes objects as small as two inches.

I don't know what I am doing, but when I have that problem, I 'select' the object and move it around with the Move tool.

When I reopen an SU file, it is often missing lines that I had, of course, previously saved. This happens about 3 time in ten. If it helps, SU typically does not connect points, in spite of screen messages assuring me that I am about to make a proper placement. Please advise.

I was working much of the day on a number of Sketchup files, properly saving after every few maneuvers. When I attempted to close one of the files a dialog appeared: "This document's file has been changed by another application since you opened or saved it. The changes made by the other application will be lost if you save. Save anyway?" Two buttons, Save and Don't Save were provided, with Don't Save invitingly highlighted. I pressed it and continued to get the same notice each time I tried to close the file until I finally chose Save. Only then could I close the file.
Can you tell me what is going on here? I wonder what sort of intrusion I have Saved and will it cause warts?