Load file from other disk using snap version

On Ubuntu 18.04 my files are not on / but on /media/DATA = another disk. PDF mix tool PDF-choice file dialog doesnt enable to access these files : when reaching /media/DATA, filedialog shows an empty folder.

PDF Mix Tool 0.4 23/01/2020 from snap.

It looks there is a snappy way to improve this using "classic" confinement : https://snapcraft.io/docs/snap-confinement.

AMOF I could finaly access files on /media/DATA using the following command first : sudo snap connect pdfmixtool:removable-media