Cannot read properties of undefined (reading 'widths')

Problem/Motivation

When accessing a form using Multiselect, console shows the error "Uncaught TypeError: Cannot read properties of undefined (reading 'widths')".

Steps to reproduce

• Create a form with a multiselect form element type.
• Visit the form page.
• Check the browser console. The error should be there.

Proposed resolution

The multiselect module loads the multiselect.js. In the line 68 there is this code:

      if (drupalSettings.multiselect.widths) {
        var widths = drupalSettings.multiselect.widths;
        $(context).find("div.multiselect-available, div.multiselect-selected, select.form-multiselect").width(widths);
      }

The drupalSettings.multiselect.widths value is not properly set and this generates the error.
As a workarround I suggest to check if drupalSettings.multiselect exist and provide a default value for widths if don't.