Issue with customizing a portableText field in Sanity.io studio

Hello! I'm trying to customize a portableText field so that I can insert references to other content. I've followed this tutorial (https://www.sanity.io/guides/portable-text-internal-and-external-links ) to add a mark in my studio, but where they show the "S" button I just have a question mark. I cannot find errors in my JavaScript console nor the console I'm running studio from. How can I figure out what's gone wrong here?

Could you share the code for it please ☺️

Absolutely!

export default {

name: 'content_internal',

type: 'document',

title: 'Content (Internal)',

fields: [

{

name: 'title',

type: 'string',

title: 'Title'

},

{

name: 'body',

type: 'array',

title: 'Body',

of: [

{

type: 'block',

marks: {

annotations: [

{

name: 'external_content_link',

type: 'object',

title: 'External Content Link',

fields: [

{

name: 'reference',

type: 'reference',

title: 'Reference',

to: [

{type: 'content_external_a'},

{type: 'content_external_b'}

]

}

]

}

]

}

}

]

}

]

}

And for reference, this is what I'm seeing. It seems to still work as intended, so perhaps it's just a UI bug?

Hey ! You'll want to add a custom icon using the method shown here .

Thank you very much, this worked!