REGRESSION: Yes
WORKING 3074157
BROKEN: 3074196
In the editor, gray buttons have white text, making them hard to read.
This was seen in the Pick Parent Class and Pick Target Skeleton windows. May be effecting other buttons all over the editor.
RESULT:
The gray buttons on the Pick Parent Class window have white text.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-34103 in the post.