Thanks. Quick check showed that WPMF does not use ‘ure_manage_options’ capability. Btw., for any permission check WPMF applies filter ‘wpmf_user_can’. So it’s possible to change, what permission it requires.
Re-thinking on the problem, I recalled that ‘edit restrictions’ set for a user automatically restricts the Media Library items available to this user – he sees only own items by default. More, if user can ‘ure_manage_options’, then ‘edit restrictions’ are not applied to him. So it would be a real reason of the described issue with access to the Media Library items inside WPMF, inspite of its internal access options.
Try to add this custom filter. It switches off the restrictions to the list of Media Library items available to a user with edit restrictions set.
