Just installed WL 10.0.20 update and checked new feature - Show Metadata while browsing in FileBrowser. I would say it works only if at least one audio file is opened and in this case this new feature is not finished in development. The Metadata pane should be available to open/move/stick while no file is opened if the metadata can be shown while browsing files. I don’t see it’s available.
If I open one audiofile, then move Metadata pane to right frame, to be visible while browsing files - yes, it works. But, if I close the file I opened just to have Metadata pane available, WL closes Metadata pane and thus the new feature isn’t available.