My Naga V2 Pro works fine with my old keyboard perfectly fine. If I plug in my new Blackwidow V4, I can no longer click with my mouse. I've tried the Blackwidow V4 Pro and my old mouse (Naga trinity). All do the same thing, when I plug in a razer keyboard it no longer will let me click.
Updated windows, synapse, usb drivers, chips etc, firmware on mice and keyboards... nothing helps