OpenMarine

All is in the title !
Whn selecting in Option/customise/ a BOLD Font and applying and validating, and closing the option by OK   the display is modified accordingly  
BUT after closing and reopening opencpn, the customisation is gone     . 
Of coursethe opencpn team should remedy, but could somebody in the team  push a little bit the opencpn team to correct that BUG. Please !?

Well that is odd because it works fine for me, whether I close/reopen OpenCPN or do a reboot. The values I set are retained.

Just for completeness, I don't recognise your Option/customise path but perhaps you've not put the complete path in. For me it's Options>User Interface, select Console Legend in the fonts dropdown, select font and colour, press Apply then OK. I suspect that's what you did anyway but wanted to be clear.

Pi 4 Model B Rev 1.5, OP V3, OpenCPN 5.8.4