File meta data popup window is empty (white) when user has no filemount access
User A creates a content element with an image from filemount fileadmin/abc/
User B has no access to filemount fileadmin/abc/ and edits the content element.
User B has all access rights to edit the content element and everything works - except when he clicks on the [i] action button (inline) the info window pops up and is white.
When the user clicks on the edit icon (pencil) he gets a message:
... Access to table sys_file_metadata for user 52 was denied ...
At least this message should appear in the popup info window.
Tested TYPO3 Versions: 8.7.1, 8.7.8