I have a multiselect filed, that should only be allowed to change by a user having a specific group. Disabling the select form field does not disable the multiselect. Despite the select beeing disabled new values can be selected via the multiselect.
In hook_form_alter() change a field to disabled:
$form['field_name']['widget']['#attributes']['disabled'] = TRUE;
If the select field is disabled, the buttons of the multiselct should be disabled and the whole widget should be given this grayed out disabled look.
Active
1.7
User interface
Not all content is available!
It's likely this issue predates Contrib.social: some issue and comment data are missing.
I have similar issue with contrib module disable_field, which can set field as disabled.
But improved_multi_select still replace such field with it's own widget.
My current workaround is to define selector with addition condition
#edit-myfield:not([disabled='disabled'])
IMHO this should be done automatically in the improved_multi_select.js