Sizing to content in markup

Hi.

The following snippet works as I expect it using JS initialization: http://webix.com/snippet/4405f6e5

Now I tried to rebuild this using HTML markup: http://webix.com/snippet/9a81e1c9

I can’t seem to get the form to adjust its height to its content. Note that I don’t want to specify the height explicitly.

What am I doing wrong?