I started a new 9.4 game and, once I had a remote inventory available I noticed that the Left hand Inventory panel scrolls just as expected using the mouse scroll wheel. The Right panel however does not, I need to manually click and drag the scroll bar to move it. Fresh Survival game start, totally vanilla so I hope re-creatable without the need of a save, though I can upload one later if required. A very short report, but hopefully containing sufficient information. Clarification: If the mouse cursor is hovering over a filled (occupied) inventory slot, mouse scrolling works on the Right hand panel. If however the mouse is over an empty slot, the mouse wheel does nothing. I generally organise my inventory slots a bit, rather than just let them fill up sequentially, so the issue is perhaps more obvious for me. Additional: Mouse scrolling doesn't work if you've picked something up. I.e. you want to take something from the Left inventory, then scroll the Right inventory to place it. Scoob.
Chose a scrollable Container,pick something from further down, then chose another container to drop it, but in the first container you scrolled down, the new opened container is also scrolled down now, with now way to scroll up, as that only works on occupied slots. EDIT: reading your post again, i guess you allready said that.....