Dual Monitors, Dual Team Green GPU, can not split desktop

I am not sure if I am doing something wrong, or it is not the best way. I Just built my new system, and the best card I could find was a GT1030. I bought it online, for I wanted to have A video card, when I picked it the rest of my parts. I get to the Comp store, and they had a Quadro 620. I bought that, for it was alot better than the 1030. I have both monitors, one on each card, with both on the desktop, configured with nvidia-config, no Xinerama. I have the desktop pic on both screens, and my curser can go on both screens. I can not move a window from on to the other, as well as, when I right click on screen 2, the desktop menu open up on the first screen. Would this have to do with the two cards and window rendering? This is the first time that I have had two GPU’s under linux. (Debian SID)