Keyes on my Kamvas 16 do multiple things

 Hi,

I'm currently trying to program the Keyes on my tablet so I can use them as shortcuts in Photoshop. For some ungodly reason, the Keyes I programmed to Control+Z and Shift+Control+Z do not exactly what they should. Ctr+Z does indeed 'Undo' but also opens the brush menu, sh+ctr+z only locks the current layer. I already tried to put the shortcuts into ps via the Keyes, but it only gives back what I programmed them to do (ctr+z, ...). Does anyone know how I can get them to do only the thing I want? It would be frustrating if I would have to use the keyboard for these very important shortcuts...