RE: Latitude E7470 External Monitors with Dock Problems
That link is for the 7240/7440. He has the 7470.
The 7470 may have the same hardware as the 7450, which has a diffent model of the Synaptics hub...but I haven't verified, and as of yet, I've been unable to find a fix for the 7470.
And the OS does not need to be reinstalled. It's not a driver issue. It's a Dell docking station/motherboard issue.
Browse the web a bit, and you'll see this problem is rampant.
Edit: Just found new BIOS released on Dell website 3/18/16...might give that a shot.