Cleaned off the desk and disconnected my ATD.
Connected the UP2414Q with a mDP to DP cable from Frys (used monitor did not come with the cable). So 4 cables to my 2013 15" rMBP: power, TB to my LaCie drives, mDP to the Dell monitor, USB to the USB-A hub port on the monitor. To the monitor's USB ports I connected my keyboard (never liked Bluetooth ones), US Robotics fax/modem, and JBL Pebbles speakers.
When I booted up...every thing worked! The default for the DP ports on the monitor is DP1.1. So I changed that on the monitor to DP 1.2 for 4k at 60Hz. Worked like a champ!!!!
I have the monitor at full 4K mode and love the crisp black text on the white web pages. IMHO, no need to scale to 1.25 or 1.5. I guess my face is around 2 feet from the screen. From what I can see, the one app that needs serious scaling of its text is Lightroom. 4K is great for editing images. But the text in the modules is far too small even with Preference adjustments.
So far one of the best $350 expenditures I have done in computing...in a long time.