USB Keyboard not detected (by Cinema display)

I use the cinema display as a docking station for my MacBook pro retina. I have a USB mouse and (apple) keyboard plugged permanently to the display.

Very often, when I dock my macbook to the display, only the USB mouse gets detected - not the keyboard (this is a very consistent behavior). For a while I was able to solve the problem by unplugging/re-plugging the USB keyboard from the display. In the last few days even that has been insufficient: I had to resort to directly plug it into the laptop ports... very annoying.

Has anybody had this issue?

Any solution?