Hi all,
It is strange that the solution is already here and is being ignored.
Have you tested Safelayout suggested by @lahos above?
I was experiencing exactly the same frustration of @guido until I installed it.
Using since months now on quite crowded layer combination on many layouts and never had one issue.
Please give it a try, I think is the right behaviour to be implemented in Rhino.
No idea about how you can make some serious drafting without it!
As we are speaking about this please have a look at this old post about Rhino 8 Development where many points are related to layout and drafting