4.6 Displaying Completions in the Echo Area

If the customisation variable completion-use-echo is non-nil, a list of completion candidates is displayed in the echo area. If completion-use-hotkeys is also enabled (see Completion Hotkeys, the hot-key characters will be displayed next to the completions they select.

completion-use-help-echo

When non-nil, a list of completion candidates (along with the hotkeys that select them, if enabled) is displayed in the echo area.