I have the same problem. But I suspect that is not working. In "XMP METADATA UI Developer's Guide" on page 5 (preface) is written as follows:
"The XMP Metadata UI (called the FileInfo dialog in most applications) is a component that is incorporated
into many Adobe® Creative Cloud® desktop applications, including InDesign®, Photoshop®, and
Illustrator®. It provides access to file metadata information through an integrated dialog or panel in the
host application."
Would be great if Adobe would answer this question concluded because this question is frequently asked.
Regards
André