Thanks for the excellent advice, but my font-menu-this-frame-only-p is
set to t (through no deliberate act of my own) and I still see the
weirdness.
Now, I hazard to point out that changing the _font_ appears to work
but _size_ changes appear to be global...
Hmmm, not that simple either. Changing _font_ in this VM compose
frame to Bembo worked. Changing size to 14 resulted in this frame
changing OK, my "main" frame's "Help" buffer to change to bembo
at
size 14 and my VM frame to entirely to bembo 14.
However, my bold font appears to have remained unchanged. My shell
buffers output fonts appear unchanged but my shell mode input font is
changed...
Totally broken...