id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
27487	ModelAdmin.formfield_overrides on ManyToManyField isn't compatible with CheckboxSelectMultiple	nrogers64		"The following `ModelAdmin` code updates the widget, as expected:

{{{
formfield_overrides = {
    ManyToManyField: {'widget': CheckboxSelectMultiple},
}
}}}

However, it has two problems:

The first problem is that it provides the little green plus sign to add another object on the fly, but that functionality doesn't actually work properly with the `CheckboxSelectMultiple` widget (after adding another object, you have to refresh the page in order to see it). So I would think that this widget shouldn't provide the little green plus sign.

The second problem might not be valid because of what I'm doing in my project. Currently, the `<form>` in change_form.html has `novalidate` hard-coded in:

https://github.com/django/django/blob/1.10.3/django/contrib/admin/templates/admin/change_form.html#L40

I have overridden that in my project, removing the `novalidate` attribute. I understand that my doing that might make this second problem invalid. The second problem is that the user has to check each of the checkboxes in order to submit the form."	Cleanup/optimization	new	contrib.admin	1.10	Normal				Accepted	1	0	0	1	0	0