Right mouse button no longer works (Evoluent vertical mouse)

I'm using a vertical mouse and after upgrading to 10.11 the right mouse buttons no longer work. It could be an issue with the Evoluent software (which I freely admit; I've emailed their support), but I'm wondering if anyone else is having problems with alternative mice and button assignments? This is the information I sent to Evoluent, which explains the problem in detail:

I just upgraded to Mac OS X 10.11 “El Capitan” and my right mouse button (the middle of the three main buttons) refuses to work. I’ve been into the Evoluent icon in System Preferences and tried “Restore Defaults” and making sure Button 2 is assigned to "Right Click", but it doesn’t work. In fact, no matter what I assign to Button 2, there is no effect.

Button 3 is assigned to “Back” yet functions as a right click for some reason. So I thought I’d try assigning Button 2 as “Back” but still, no right-click result. No matter what I assign to Button 3 I still can’t get it not to function as “Right Click”, either.

I’m using Evoluent Mouse Manager for Mac v 1.0.10 and as far as I can tell it’s the latest (which is dated 2013-10-18 on your web site, and my Macbook Pro is newer than that, so I would have installed this version).

I found this on the Adobe forums where someone has reported their right-mouse button no longer working in El-Capitan. It adds to my suspicion that something in the OS X 10.11 is wreaking havoc with people's mice. I have an external Dell 27" monitor connected through an official Apple DVI/thunderbolt adapter, but disconnecting it and connecting the mouse directly to the side of my MBP made no difference, unfortunately.

I know this isn't an official mac input device, but somehow, something in El Capitan has made life difficult for other mice as well.