Is your feature request related to a problem?

In cases where original cell ids are used, it would be handy to have a toggle that shows all the cells for debugging and general understanding

For example, you can learn something if there is no difference between using the orig cell ids and not using them, or if you do a LOD refinement it can be good to see "how big" the refined mesh is.

Is your feature request specific to a data set?

Helpful for MFEM data.

Describe the solution you'd like.

New option in the mesh plot, we should brain storm the proper name.