Hi, if a file is grayed out it means that it was not uploaded by the plugin.
The File Browser is meant to manage files that were uploaded by the plugin.
However it can also manage other files that were not uploaded by the plugin, you just need to include them in the plugin’s database.
To do that, go to Settings and enable option “Include Other Files in Plugin’s Database”.
Then you will be able to Include files from the File Browser and then you will be able to delete or move them.
Regards
Nickolas