When you click the different tabs for Rotom's forms, the typing data and the sprite change; however, the weaknesses/resistances data doesn't. Is it possible to make it so that it does change with the rest of the data?? (I haven't checked any other Pokemon, but I can't remember if Rotom is the only one who's typing changes with his forms; probably Wormadam, as well).

Just checked Wormadam, and his changes, but Rotom's doesn't.

It's changing perfectly fine for me. Only thing I can think of is that you must be viewing the DPP and HGSS data - it shouldn't change there. But under the BW data (which is the default view), it changes like it's supposed to.

Oh, maybe that's it. I'll try changing it, thanks!