SharePoint File Picker Has No Select/Ok/Confirm or Cancel Buttons

[jim-r-gs]

When the popup for the SharePoint/OneDrive v8 file picker opens, there is no Select/Ok or Close user action buttons like there are with the consumer OneDrive file picker:

Files can be selected but there is no way for the user to tell it to pass the files pack to the application and close the window (or just close the window/cancel selection).

How can I get buttons to appear to allow the user to confirm their file selections?