Geany cannot display help, missing browser command firefox

I am trying to use geany, but when I try to get help, a popup appears that tells me that the browser command is misconfigured:

I tried several other commands, ie. firefox-bin (which is what I can see in the process list), flatpak run org.mozilla.firefox (which is how I succeeded to start firefox from the command line), but without success in getting help in geany. I also tried to adjust access rights for geany with flatseal, but did not succeed. Any suggestions what to enter as browser command and/or how to adjust the permissions?

eos-diagnostic-210913_104655_UTC 0200.txt (1.1 MB)

Can you report this issue to the Geany Flatpak maintainers at ?

It appears that they have already made an effort to resolve this but evidently that fix was incomplete.

done, see: and as @wjt suggested there substituting xdg-open instead of firefox works.