When using a windows scaling (such as with 4k monitors) the New editor windows position is not retained between play sessions. The window is always centered. This does not occur if windows scaling is set to 100%
Result: The window is no longer in the position it was moved to previously
Expected: The Windows position would be retained between sessions of Play
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-58037 in the post.