v. 12 upgrade creates problems in environments with mixed Retina and Not-Retina displays

I use a MacPro 5,1 running El Capitan. It's connected to a Samsung 27" non-retina display (that acts as my primary monitor) and a Dell 32" 4K monitor that was used as a secondary display at 2,560 x 1,440 HDPI (with the help of SwithResX). Parallels 11 allowed me to run my VM at full screen at that resolution without any issues. Since upgrading to v. 12 however, Parallels sees the Dell display resolution at its native 3,840 x 2,160 only and does not seem able to support alternative resolutions. Your help would be much appreciated

 

Hi PetrosP1,,
Check this link & let us know how it goes.
Thanks.