Not working on Preact

[danibram]

Hello!
Thanks for this awesome library, I have a problem that te library is not working fine on preact, I made a fast example with codesandbox, its like one panel works fine the other for any reason no... (If you see the panel "Example works fine" the other not works, happens the same if you have more pannels only the last one works) =(

Here you can reproduce:
https://codesandbox.io/s/preact-allotment-bug-gkdkzv