Remounting of ReflexElement children when collapsing panes

[adri1wald]

Hi, loving react-reflex, but I found a bug which prevents us from using it. Unless we can find a solution :D

I took the example from react-reflex collapse demo and tried to adapt it for our app.

However, I noticed that components rendered in non-collapsed ReflexElements were remounting on collapse, causing loss of state.

I made a minimum reproduction which shows that the ReflexElement child is being remounted on collapse. If you collapse one of the panes, you will see mounted logged to the console.

[leefsmp]

I just passed a key on the middle ReflexElement and it seems to solve the problem:

<ReflexElement key="middle-pane" minSize={100} className="middle-pane">
    <LogMount />
</ReflexElement>