Creat a trait

[JuniorVezintana]

Any ideas on how to create a trait for the 'details' tag that applies open to the tag, so that it is open by default or closed if the checkbox is already unchecked?

[artf]

This is the default behavior of the trait checkbox type

attributes: { open: true }, // e.g make it checked by default
traits: [
  {
    type: 'checkbox',
    name: 'open',
  },
]

[JuniorVezintana]

For me it's not standard, in any element or block, only the id and title come, I can't add any other trait to any element!
Maybe I'm adding it wrong. Are traits defined in the block or at initialization?
////////////////////////////////
$this.objBlocksDefault['section-ini'] = {
label: 'Seção',
category: $this.strBlockText,
media: <img src="https://cdn.plices.com/assets/app/builder/svg/column-1.jpg" style="width:100%">,
attributes: { class: '', title: "Adicione uma seção ao layout" },
editable: true,
draggable: true,
selectable: true,
resizable: true,
trait: {
type: 'color',
// ...
},
content: <section style="width: 100%; font-family: inherit; min-height: 150px; display: flex; flex-direction: column; justify-content: center; align-items: center; box-sizing: border-box; padding: 10px;" data-gjs-resizable="true"></section>
};

[artf]

Maybe I'm adding it wrong

yes... you're confusing component properties with block ones, please read carefully the documentation.