MCU Setting not inherited by subfolder
Dear LaurentL,
the problem is not with the main project. I specified my board correctly there.
The problem is with manually created folders (other than "Src") in the project at the root level.
These sub-folders (I use a virtual folder "Common") do not inherit the compiler settings from the parent project.
To be clear, when I right-click on my sub-folder, there is not "Target" tab on the page: "Properties -> C/C++ Build -> Settings" . Only the "Tool Settings" is available there.
That's why compilation fails.