Doc.ValidateButton reloads the page. Not consistent behaviour with Doc.Button

[semuserable]

I assumed that Doc.ValidateButton works as Doc.Button from UI.Next, but I was wrong. It constantly updates the page after click event. I resolved the problem adding the following attribute attr.``type`` "button". Was this behaviour made intentionally?

UPDATE

Ok, I understand that <button> defaults to submit type when placed in form. Nonetheless, maybe to explicitly add type='button'?