LibreCAD normally keeps it's toolbar settings over a restart. Maybe something is wrong with your installation. In the case of Windows I think the settings are stored in the registry. Ah, now I see you are on Linux Mint. Sorry, I have no clue what could be the reason.
On Ubuntu, I have a configuration file in ~/.config/LibreCAD. The file LibreCAD.conf contains my preferences. You can check if this also exists on Mint ?
Hello,
apparently everything became ok, my spréferences remained in place. I cannot explain.
I checked, the file is in place.
~ / .Config / LibreCAD
Thanks for your help