While cycling through a zsh completion menu (via TAB, SHIFT-TAB, or whatever is bound to menu cycling), I want to not update the command line until a menu item has been chosen (via ENTER, SPACE, or whatever is bound to making a choice from a menu).

I can/will modify the completion script.

I don't care how it's done, either by zstyle, compadd, or some other compsys function, etc., though, obviously, I'd prefer it to be as simple as possible.