How can I expand has_many field?

[HeppokoNeet]

I want to expand has_many field.
When I try this code

field :evaluations do
        required true
        html_attributes rows: 30, cols: 50
      end

it doesn't work.
seems working only normal field.

How can I do that?

[codealchemy]

For cases where the form_filtering_multiselect is used (which is what appears to be the case ☝️), I don't believe html_attributes will have any effect (since the widget overrides the select in the template that those attributes are passed to) - you'd need to look at updating the CSS for that widget.

ex. to adjust the width / height of the multiselect (globally):

.ra-multiselect > .ra-multiselect-column > .wrapper > select {
  min-width: 400px; // default 200px
  min-height: 200px; // default 120px
}