Gemalinen..
The three lines menu, nick name: Hamburger menus, down right is for "What's on the actual chart canvas"
The upper left Hamburger is for
OpenCPN options and plugins.
In options the "Vector chart display" has some general settings.
See my examples for a possible start of settings to try.
More here by the link on the
OpenCPN download page:
https://opencpn.org/OpenCPN/about/ver520.html