Wrong default saving location, & beyond that user can not change it !

Hi. I tried this package. I noticed that default saving location when I tried to save newly created PDF is pointed to wrong location which is:

run/user/1000/doc/--------

where ------- is something like "kfdjuh37"

I faced with such issue with pdfslicer & it's developer fix it - see: https://github.com/junrrein/pdfslicer/issues/72

Also, I faced with such issue with PDF Mix - see: https://gitlab.com/scarpetta/pdfmixtool/issues/13

The diffirence with Master PDF Editor is that even when I select other location like /home/myusername/Desktop & save, the document saved to same wrong location !! So, in pdfslicer & PDF Mix it was possible to overcome this issue when user change location to other one. But with Master PDF Editor even this work around not working at all !

Start by reproducing a PDF save in the Flatpak and compare the default path with the selected destination. Review the behavior described in this issue and the linked pdfslicer and PDF Mix reports. Done means newly created PDFs save to the chosen location instead of run/user/1000/doc/--------.

Written by the indexing model from the issue text.