Maybe that is your problem then. I don't know why I get two, but I know others do as well, I read it somewhere else on the forum (although I can't find it now). Maybe you could find something in dconf-editor to set the shortcuts. The entries for keybindings are all over the place in there, here are just a few of them:
(You can press ctl/f to search in dconf editor).
Fujitsu Lifebook AH532. Intel i5 processor, 6Gb ram, Intel HD3000 graphics, Intel Audio/wifi. Realtek RTL8111/8168B Ethernet.Lubuntu 13.10,Ubuntu12.10 (Unity), Mint16 (Cinnamon), Manjaro (Xfce).