Hi,
The problem stated immediately after the 1.1 update. I redefined the mouse buttons to try to overcome the problem, and the button functions are now back to the default status. Middle button still works fine for everything else. It's just the wagons filters.
Thanks.

Just updated to 1.1.19 (build 57957,win65) and I can no longer use the middle mouse button (MMB) to filter slots in the wagons, a feature I used a lot previously to protect incorrect filling of wagons on the service supply train. (Supplying repair packs, artillery shells, etc. to remote mines).
The ...