on Windows: magit-commit-popup returns error. Buffer is read-only

[sudurais]

When key 'c' is pressed from magit-status window, it takes to magit-commit-popup buffer and another key 'c' press, it returns error saying
call-interactively: Buffer is read-only: # [6 times]

Magit 20160425.430, Git 2.8.1.windows.1, Emacs 24.5.1, windows-nt

C-h b points to below data. It seems that, c isn't working in popup mode. Is there any workaround for this?.

1 mykie:global-map:1:self-insert-command
2 mykie:global-map:2:self-insert-command
c mykie:global-map:c:self-insert-command
i mykie:global-map:i:self-insert-command
j self-insert-command
k mykie:global-map:k:self-insert-command
n mykie:global-map:n:self-insert-command
o self-insert-command
p mykie:global-map:p:self-insert-command
w mykie:global-map:w:self-insert-command
z mykie:global-map:z:self-insert-command

[yuutayamada]

seems magit doesn't allow user defined functions in global-map's a-z key...

I made sure following code (without mykie package):

(global-set-key "c" (lambda () (interactive) (call-interactively 'self-insert-command)))

though not sure how to solve