BaseX: How can one delete an XML file from disk?

I am trying to delete a file from hard disk using BaseX 7.9 GUI. First, I set WRITEBACK to true:

I then make sure it has been correctly set using db:system(), having the following result:

<system>
    ...
    <writeback>true</writeback>
    ...
</system>

Finally, I perform db:delete('db','test00001.xml'), successfully removing the file from de databse. However, when I go check on the file's actual directory I find the file is still there.

Is it possible to delete a file from hard disk with BaseX GUI. Is there somthing wrong with the way I am trying to delete the file? What would be the right way?