I swear that at one point, I used to be able to horizontally scroll in the clips pane and the PRV by tilting my mouse wheel. But at some point it stopped working. It may have been when I uninstalled the Logitech software and just let Windows handle the driver. But my mouse wheel tilt-scrolls in other apps (browsers, Excel etc). 
 
Having just installed Sonar from scratch on a new rig i was kind of hoping I'd be able to horizontally scroll again but alas, it was not to be. Is there something I can do to enable this? Will installing the Logitech mouse software make it happen? I'd rather not do it because I've had problems in the past with the Logitech app. 

Ctrl+wheel scrolls left right for me (default settings). I just tried using the wheel tilt on my Logitech mouse and doesn't work. I have never used that before, so not sure if it ever did.
 
Edit: I just tried to manually assign it with the Logitech app and do not see a way to assign "Ctrl+wheel" You can select "Keyboard Assignment" and it will accept the "Ctrl+" but does not read the wheel movement.

No tilt wheel here so I have to CTRL+wheel

Scrolling horizontally is working for me when I tilt the mouse wheel. I'm using a Logitech M705, driver version 5.60.73 on Win 8.1 x64. Sonar X3e.

So a mixed bag of experiences. At least I know it's possible with a Logitech mouse then. I CTRL-wheel too, but you know how it is, sometimes you just don't wanna reach for the keyboard 

I have the M705 as well, but my driver version is 5.33.10.0 (Win7). I just checked and there is a 6.61.15 version available. (After installation, the driver version says 5.60.66.0.)
 
Edit: I just downloaded SetPoint 6.61 and the wheel tilt scrolls now. I free-wheel the mouse wheel, so the tilt seems slower than molasses to me. Adjusting the acceleration makes it better, but....
 

I don't seem to be able to get my Logitech G500 to scroll using the tilt wheel. This is only in Sonar.

You can scroll vertically with the mouse wheel??? How did I not know this? Thanks for the tip!!

Hmmm, I shall rotate my mouse 90 degrees and try it :).

I think there is not a good way to do this, i'll tried many ways that guys said, but i can not fully solve my problem.