Zoom Extents issue / question

I applied the advices from the other discussion (eneroth3’s codes) in which you wrote. But this is a temporary solution.
Normally it is good to learn how to draw correctly from the beginning. Group the raw geometry by type, then assign layers. After that you add texts and dimensions, on their own layers. And you also could use Scene for presentation.
Keep in mind that Layers do not separate geometry, they are just like tags.