When you are quilting charts
(or stitching them together) with different scales, OpenCPN
displays more or less details depending on the scale difference.
As it is an impossible task, to give a general solution for all existing mixes of charts
, there is an option to optimize the behavior for your chart set.
You will find this tool at:
Options|Display|advanced --> the slider for Chart scale/zoom Weighting for vector charts in this case.
Go to +3 or +4 and have a look what you like most.