Open With... GIMP Flatpak Version

[XnViewOnLinux]

I have been using and enjoying XnView MP on Linux Mint for quite some time. I added the GIMP executable to the Configure Programs dialog quite some time ago and it works great. The Linux Mint repository is a bit behind on the GIMP version so I installed the latest Flatpak version of GIMP.

The problem I'm having is that I can't get it working in the Configure Programs dialog so I can use "Open With...".

The path being used by the Linux Mint start menu is '/usr/bin/flatpak run --branch=stable --arch=x86_64 --command=gimp-2.10 --file-forwarding org.gimp.GIMP @@u %U @@' (without the single quotes).

I tried selecting the executable /usr/bin/flatpak and adding the rest to the Parameter field but that doesn't work. Any help would be appreciated.