Aha --- now it works. My problem had not been a failure to make a
selection, but rather that, having seen that my selection of the formula
cell had moved to the two prior cells, I had RE-selected the formula cell
before hitting Delete. It works.
But --- now I have another question.
Is there any particular advantage doing it as Ferrero had suggested, versus
using fewer keystrokes and mouse-clicks and just selecting the first two
cells and hitting Delete?