Resizing a text input field

Using tabs, I can create a dedicated tab to enter longer text.
While the Studio correctly displays the text input field in its full specified size of 80% within a stylebox which in turn has 100% size within the tab, the Preview always sets it at the default height of 30px.
Is this a bug or where am I wrong?

Hello Tilman!

Did you try setting the height of the embedded input part of your text input?

I went from outside in and set everything to 90 or 100%. I got completely rid of any height spec in pixels. And as I wrote, it looks perfect in Studio, but in Preview it sticks to the default height.