This issue has been closed as 'Won't Fix' due to an extended period of time without updates. If this issue is important to you please let us know by posting on the AnswerHub or UDN, and Epic will re-open the ticket for further review.
Screen position does not appear to work when used in UMG. The Material appears to be one solid color.
Head over to the existing Questions & Answers thread and let us know what's up.