Unable to receive resolutions for Mac

Hey guys,

I have a question regarding receiving current monitor’s supported resolutions.

Right now, we receive monitor’s supported resolutions using RHIGetAvailableResolutions(). However, when we do this to Mac, we get no value, and in the codes, the value in the MataRHI.cpp only returns false. So to get resolutions through OpenGL, I changed the codes in ProjectSetting=>Platforms=>Mac so that it doesn’t use MatalRHI, but it still doesn’t change to OpenGL.

So what I want is I want to receive supported resolutions using MatalRHI. If it’s not possible using MatalRHI, anybody knows how to do change this to OpenGL?

Here’s our current environment.
UE4 Version : 4.11.2
OS : OS X El Capitan