I recently needed a layout whose height would be automatically set to the sum of heights of inner child elements. So when there are TextInputs and the user writes more lines of text, the layout will suitably change its height.I have succeeded, and you can see the (almost) minimal example here:
http://pastebin.com/rgFnLX9A

It does not work on inserting just a end of line char (‚\n‘) though, as it does not generate the on_text nor the on_focus event. I don’t know how to overcome this.