Automation Working in Edit Window but not Mix Window

[jakesnowdog]

I'm using an old version of Pro Tools (M-Powered 7.4) on a PC (sorry I'm old and on a budget and it's working great for what I need it to do EXCEPT for this automation issue).
I just recently learned all all about automation. It's working 100% for me when I use the tools in the edit window on my tracks (so I'm glad about that) - BUT for some strange reason it's not working when I try automate using the Mix window faders or pan levers (like I have seen working in many tutorial videos also using my same version). Does anyone know what might be causing this? Or what the fix would be (besides the obvious buying a new PC and latest version option)?

Thanks in advance for your time and consideration.

FTI - I do have the very latest updates for this version that were available.

Jake