Hi Harlam,
thanks for fast answer. I searched my local linux user environment and found that file (the "..." are synonyms):
"/home/.../.local/share/harlam357/HFM.exe_StrongName_.../user.config"
There are the user settings stored, but unfortunately in my case only the FormSizes, -Locations etc. The preferences settings are not stored. I edited the wanted settings from HFM.exe.config in that user.config before starting HFM.exe an they are loaded correctly.:) But at exiting the application they are overwritten ;( So I made a little script that creates the actually used user.config from a template with my wanted settings before running the application. It's only a workaround, but usable for me. Your naming of the properties is plausible, so I'm able to customize my template by editor instead of graphical preferences interface.
I know, that the mono runtime environments highly differ between linux distributions, their versions and every user installation and it's not easy to consider all cases in development. If you are interested by any help from (debug logs etc), let my know.
Best regards, Matthias