Hi and thanks again for tips!

> This should be:
>
>   (defvar project-prefix-map
>     (let ((map (make-sparse-keymap)))
>       (define-key map ...)
>       ...
>       map)
>     "...")
>
>   (define-key ctl-x-map "p" project-prefix-map)
>
> See the end of (info "(elisp) Tips for Defining").
>
> Maybe it should also be autoloaded.

Below is another patch with your suggestions incorporated. Is it correct to also autoload the (define-key ctl-x-map "p" project-prefix-map)?

Theo