Unable to use full resolution of P2416D Dell P2416D (Vendor 10AC, Product A0C3) is 2560x1440, but my Mac OS X (on Macbook Pro Mid 2010 connected via Thunderbolt with Mini Display Port cable) doesn't have corresponding file in /System/Library/Displays/Overrides and when I used the SwitchResX Control application taking values from http://content.etilize.com/User-Manual/1030957703.pdf after reboot this settings were stated as "invalid": 



P.S.: the https://gist.github.com/adaugherity/7435890 didn't reveal the desired resolution.
I jut had to connect to Display Port instead of HDMI.