I highlight from the bottom up. I start with the cursor at the last character in the post, holding the left mouse button down I move the pointer the the spot just to the left of the date in the upper right hand corner.
That's GOBUCKS' system too, and the easiest.
However, when the new DU came into being, as I couldn't figure it out, what evolved was something that requires two, not one, copy-and-paste jobs, per each primitive comment. By the time I learned of GOBUCKS' method, I was used to this other way, and reluctant to change.