[GNC] Document Link Action Freezes Flatpak GnuCash

[George Lobay]

I'm using the latest Flatpak GnuCash, ver 5.6, on Linux. Everything 
works fine except:

Document linking does not work. I thought it might be a permission 
problem, but GNC does have permission to access the folder that holds 
the documents to be linked, confirmed by Flatseal.

Problem in detail: Right-click on register item, click item "Manage 
Document Link", dialog box opens. Path head is set to the default 
Documents folder, the file selection button says 'none'. All is well so 
far, then click 'none' and then GNC completely freezes (including the 
dialog box), I have to use xkill and restart GNC. Happens every time.

I really thought it was a Flatpak permissions issue but apparently not. 
When I use the non-Flatpak older GNC that comes with my Linux 
distribution, there's no problem.

Thanks in advance