On the back of the display, facing downwards, you will find these ports. Be careful not to use the DisplayPort Out by mistake.
To connect two Macs at 2560×1080 resolution you will need an additional Mini Display Port to Mini DisplayPort cable, like the white one shown here.
The cables connected, with USB 3.0 (uplink) cable shown on the right.
The display has 2 USB ports next to the uplink port behind the display and 2 more on the side which frees up the 2nd USB port on the MacBook Pro.
The display at full (2560 x1080) resolution 
Thanks so much for your set up instructions. I have the same configuration as you…however, when a video plays – there is a blue tint that only overlays the video (youtube, imovie, etc) Have you seen that issue? Dell was no help. Just wanted to see if any other users had the issue.
Yes. Go to the bottom of the comments on the last page
this was exactly the problem
thanks!!!!!!
You showed us that there is a DP out for daisy chaining, Is this possible with a MacBook Pro? Kind of like the same thing the Apple ThunderBolt Display uses?
Hi Dylan,
Sorry I don’t have another display with DP in to check but it should work. (It might be better to ask someone at Dell. It’s possible that it only supports mirroring and not extension for example.)
Darren
Further to this question, it seems that the Dell monitor/Mac combination only supports mirroring.
https://discussions.apple.com/thread/4740489?start=15&tstart=0