Senzless

I have one of these (image below), a ‘wind-proof’ umbrella.

The idea is that the umbrella is so-shaped and so-design such that it won’t turn inside out when you least need it to.

I suspect there is an easier way to solve this problem; just fill up the space under the umbrella so that it isn’t concave any more, just flat.

All that is needed is a second membrane for the purpose – see second image for concept.