Martin

@jrogatis I'll try and we'll see what happens :).

I think I do not have enough understanding of React to do this yet so if anyone else wants to work on this go ahead.

@ghackebeil that looks really great! It would still be nice for the pyomo.core to support subclassing. I'm working with a very large existing code base and switching the entire code...

I mean the issue is still valid afaik, but if the decision is Pyomo doesn't have the interest/time to implement a fix then it would make sense to close it....

Hi @dcherian! Thanks for the response. I feel that it would be best if `.fillna()` was performant by default rather than requiring a workaround or users to write code manually....

(I might be able to submit a pull request for the proposed solution but I first wanted to hear what you thought @FabianHofmann)

**Update on investigation** I took a look today at adding support for `sparse` however the changes seem to be quite invasive for two reasons... 1. `xarray` is [still developing support](https://github.com/pydata/xarray/issues/3213)...