A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
I think this is fixed.
No, really, if you have Excel 2016 Version 1710 (Build 8625.212 Click-to-Run), it is working. Both ways - I can scroll Excel if another window is in focus, and another window if Excel is in focus.
Please try it and let me know I'm not hallucinating. :)
ETA: OK, halfway. I can consistently scroll an inactive Excel window, but I can't consistently scroll another inactive window if Excel has focus (I'm playing with it to see if other programs are also not honoring the setting - one of them is iTunes, and we know what a mess that is)...