partial section on half view

[Login]

Good morning to all,
as from title, I need to dissect a part of model represented as half view.
I create 3.0 but it only allows me to select the complete section, while all the others are not selectable.
Is it a setup problem or is it just a version 3.0 limit?

 

[arni1]

total view,
Local section
then join the section, which cuts the half view

Hello