Right Control is acting as a forward slash /

I'm using Slackware 14.2 running XFCE in my computer. I've noticed that my right control key is behaving as a forward slash /
I tried:

• Login as root and tried: KDE/XFCE/FluxBox, and so on, no problem (Right control works as a normal Control Key, as expected)

• Login as my user and tried: KDE/FluxBox/BlackBox: no problem, except when I run XFCE

So, I suspect this is a problem in some XFCE config related to my user, but I don't know what is going on or even what place I can go to fix this problem.