I replaced the 2-button PS/2 mouses on a few PCs with my favoured type of wheely-scrolly Logitech ones. I ran mouseconfig and told it that I had a MouseMan+/FirstMouse+, which is roughly what they are. It offered to update XF86Config, and I agreed that that might be a good idea. But, while I could paste with the middle button, I couldn't scroll in gnome-terminals, as no ZAxisMapping line had been added to the "Pointer" section of XF86Config.
This is fixed in the next release... (and pinstripe)