I wrote this, but then found I was entering the menu with one press. It seems the trap is to not have the correct menu called with the button, and then one relies on the balloon to get in. Disable that as well, and one is SOOL.
The big issue with this Sony VPCF125FX seems to be that one has to click on the balloon to access this S1 menu system. Indeed, that's why it took me so long to find it. One can turn that balloon off in the menu, but then I can find no way to get to the menu to turn it on again. Very, very strange.