35 years ago I had an original 48K Sinclair ZX Spectrum. I never had any of the Plus or 128K models and practically never even touched one as I moved onto the Amiga quite early.
I'm now playing with some Spectrum emulators of those later Spectrums. Some of them including the 128 have a boot menu where the user can choose a couple of modes or actions:
Now I feel very stupid, because I've tried all the key combinations I can think of and I've spent about 20 minutes Googling, yet nowhere can I find out how to move the cyan bar up and down to select which action to take! It must be so incredibly obvious to the initiated that it is never discussed on the internet using the search terms I've been trying...
I've tried the PC arrow keys, the number keys, and all over the keyboard using either the left or right shift keys (caps shift vs symbol shift).
If it makes a difference I'm using the Spectaculator emulator. Even its on-screen keyboard and keyboard map features don't provide me this vital clue. What am I missing?