How to set a default selection on the Jimu Multiselect control?

[DominicRorke1]

I've developing a custom widget for Experience Builder, and I'm having issues implementing the Jimu Multiselect control, documented here: https://developers.arcgis.com/experience-builder/storybook/?path=/docs/components-jimu-ui-index-mult...

I can populate the multiselect with items, and I am capturing the item click event.  What I can't work out, is how to set a default selection.  When the multiselect is first opened, it looks like this:

And I want to be able to check some of these items by default, such as this:

I've tried implementing the 'defaultValues' property, but with no more than the very limited documentation provided by ESRI, and a storybook component that crashes when I click 'Set object' for this property, I have not been able to get this working:

Here's my code for reference (without any attempt to set default selection):

<MultiSelect

      onClickItem={(e, value, allSelections) => itemClicked(e, value, allSelections)}

      displayByValues={function noRefCheck () {}}  

      buttonProps={{

        size: 'sm',

        icon: true,

        title: 'Toggle columns',

        className: 'btn_columnToggle'

      }}

      items={[

        {

          label: 'Item 1',

          value: 'item-1'

        },

        {

          label: 'Item 2',

          value: 'item-2'

        },

        {

          label: 'Item 3',

          value: 'item-3'

        },

        {

          label: 'Item 4',

          value: 'item-4'

        }

      ]}      

    />

    </div>

Appreciate if you can help me with this, as I'd quite like to use this Jimu component.

ESRI - Please improve your documentation for the Jimu component library, and for Widget development generally.