System Information
MacOS 10.14 Mojave, MacBook Pro (Retina, 15-inch, Mid 2014), Intel Iris Pro / NVIDIA GeForce GT 750M

Blender Version
Broken: (Version 2.80 2018-09-28)

Short description of error
Looks like blender don't recognise scaling of resolution of retina display and show blender in full resolution and and on start you see only quarter of blender. Left bottom part.

Exact steps for others to reproduce the error
It happend on start