Issue with flexbox

[fabthegreat]

Hi, thanks for this wonderful forking job.
It looks like flex-shrink is not compatible as the board is not shrinking when I resize down the window.
I can grow however but never shrink back...
Do you have a tip?

Here is a simple prototype

Thanks

[fabthegreat]

I just figured out that setting a min-width almost solve the problem... Why that?