x-model.fill doesn't support textareas

[saveman71]

I'm not sure if it's a bug or intended, but x-model.fill doesn't support textareas at the moment. I feel like it was just an oversight of the original implementation, as textareas work quite differently under the hood.

Is this a bug?

There's this PR #3495 that adds support for selects.

[ekwoka]

As discussed in #3495 that change will support everything that x-model already works with.