Hello everyone. So I am having a very annoying problem and no one can figure it out, including myself. I've been to the Genius Bar three times and I have had both my bluetooth keyboard and Magic Track Pad replaced, which hasn't solved the problem. The problem I am having is that when(and only when) I am connected to my external monitor with my 2015 MacBook in clamshell mode my Bluetooth keyboard and track pad stutter. My trackpad cursor moves erratically and typing is slow to show up on the screen. I have found a thread on Apple's support website where there are 13 pages of responses about this same issue but no one can figure it out; except one person said the wrap the HDMI cable from the monitor to the MacBook in aluminum foil!!! I have exhausted everything I can think of. The only thing that I can think of that could possibly interfere with the bluetooth signal is that my Netgear Nighthawk X4S router is within about six inches of my MacBook when its docked, in clamshell mode. Help!!! Any suggestions and or fixes would be greatly appreciated!