Well, normally.. using CoreDisplay stock binary from 10.14 Beta; what error appearred on Console's log when switching from Dark to Light mode was:
Code:
WindowServer (IOAcceleratorFamily2)...
...but, with CoreDisplay from 10.13.4 what I get is:
Code:
kernel (IOAcceleratorFamily2)...
So, I think.. a weird grayed Top Menu Bar with LightMode appearance is not caused by CoreDisplay (though, I could be wrong for sure). Graphics acceleration under 10.14 Beta (18A384a) are still working fine with 10.13.4's CoreDisplay (on my case), but.. it doesn't fix this Top Menu Bar issue. FYi only.