`use-package` and `define-key`

Question

I'm using multiple-cursors, setting it up with use-package. By default, when multiple-cursors mode is enabled, <return> is bound to multiple-cursors-mode. I'm trying to override that adding this after :config in the use-package declaration:

(define-key mc/keymap (kbd "<return>") nil)

So, this is part of my init.el:

(use-package multiple-cursors
  :ensure t
  :bind (("s-d" . mc/mark-next-like-this)
         ("s-D" . mc/mark-all-dwim)
         ("s-L" . mc/edit-beginnings-of-lines)
         ("s-<mouse-1>" . mc/add-cursor-on-click))
  :config
  (define-key mc/keymap (kbd "<return>") nil)
    )

Unfortunately, when multiple-cursors mode is enabled, C-h k tells me

<return> runs the command multiple-cursors-mode (found in mc/keymap)

I tried putting the :config bit before :bind just in the off chance it had something to do with the way :bind works, but that didn't make a difference.

Answer 1

Reading the source code (of multiple-cursors) helped me with this one. :)

This key is defined in file multiple-cursors-core.el and the end of this file provides the feature multiple-cursors-core, so you have to use-package this feature.

(use-package multiple-cursors-core
    :bind
   (:map mc/keymap
         ("<return>" . nil)))