Setting an element default value is confusing

The "steps to reproduce" do not include the "Update default value" step, which is what I see when setting a value. Do you not see the following?

After selecting "update default value" and saving the element, the default value works.

Thank you for clarifying!

I misinterpreted the button "set default value" as a submit/save button for the value, since one can enter a value in the textfield above.
Maybe we should make the textfield in my screenshot disabled? - It makes no sense to allow someone to edit it.

It appears the "set default value" is only a link to another form, which contains the actual submit button from the screenshot in #2. And after clicking "update default value", it is also necessary to save the element itself with the blue save button at the bottom. So the submit button "update default value" isn't a save button, but a "go back to the form" button.

UX-wise, it would be a lot cleaner if we remove the "set default value" button, let the user enter the default value in the textfield (with the green border in the screenshot above) and let them save it using the blue "save" button at the bottom in the advanced tab. No need to open another form. This way it works the same as all other fields in the advanced (and other) tabs. Even the "clear default value" can be removed, so users can empty it themselves? After all, there isn't a "clear wrapper css classes", "clear help title" and so on... either.

What are your thoughts?

I agree the UX is not ideal. There is probably some history here in this issue queue as to why the situation is the way it is. It looks like #3260016: Default Element Value cannot easily be CLEARED once set → is part of the story.

This needs an issue summary update if it is going to be the issue that improves UX.

The 'Set default value' button opens an instance of the input based on the currently entered settings and validation rules. For more complex elements, including composites, we need to rerender the entire element.

I am not sure we should make any changes to this behavior.

I see. Can we make the field disabled so it becomes less confusing?

I am hesitant to make any UI/UX changes, but the field could be disabled via a form alter hook.

Ok, no problem. Thank you both for the swift replies!