I want to use so called natural scrolling, i.e. reversed scrolling with the mouse wheel. I can do this in Lubunu 14.04 (i.e. LXDE) by editing
.Xmodmap in the home directory to contain the string
pointer = 1 2 3 5 4 6 7 8 9 10 11 12
Now, this has the annoying side effect that the scroll direction is also reversed when minimizing and restoring windows by scrolling on the task bar (the panel). In the task bar settings you can only click whether you want to use the mouse wheel or not (see screenshot), but I cannot find out how to reverse the meaning of up/down scroll so that a window is minimised when moving the finger tip on the wheel towards you, which I believe is the natural way in this context.