Is it possible whilst editing a sketch to prevent selection of visible background part geometry? Sometimes it seems like clicking on sketch entities leads to background part geometry being selecting in preference, which seems backward/counter-intuitive/less than helpful.

In CATIA, for example, there is an option during sketching to toggle whether you can select background geometry or not or eve to just completely hide it all temporarily to reduce confusion.

When I edit a sketch in an assembly context, I find it impossible to select a dimension to either move it or delete it.

Thanks in advance.