USB Keyboard disables Dock
I have a MacBook running El Capitan and when I plug in a USB keyboard to use I cannot access the Dock. I can SHOW the dock, but I cannot hide the dock and make it show by moving the mouse to the bottom of the screen. Won't work by moving it with a mouse. Won't work moving it with the trackpad. Won't work moving it with a trackball. Only way to get the dock to work again is unplug the USB keyboard.
Oh did I mention it;s an Apple extended keyboard?
Any ideas? Thanks,
John
MacBook, OS X Yosemite (10.10.5)