Proportional height not set

Hi Enrico,
thank you for your plugin.
I’m trying to make it work as “default setting” (no width set) but I can’t because the map height and max-height are always set to 0.
If I set the width to 100%, the height is really small.

You can find an inspector view here of the rendered html:
https://interser.totan.us/wp-content/uploads/2018/05/Schermata-2018-05-29-alle-16.38.13.png

Can you guess what’s the problem and how could I fix it?
Thank you in advance for your help,
Matteo