Mousewheel operation

[tony mollica <tjm3@threedogs.net>]

For the last two days I've been trying to find some information on this 
problem:
I used to be able to use the mousewheel left-right to page back and 
forward in
history in Firefox.  Unfortunately, I upgraded three things at one 
time:  the usual
Debian updates, Firefox from 29 to 30 and Mate from 1.6 to 1.8, and now I'm
unable to find the location of the setting to make this work again.  I'd 
appreciate
any suggestions on where to look to fix this.  I'm thinking Firefox but the
mousewheel parameters are a bit cryptic.

thanks,
tjm