I have created a kitchen with base units topped by the countertop with hole from the Revit UK library - Counter Top w Sink Hole.rfa. I then placed a standard sink unit - Sink - Kitchen (7).rfa, and a cooker hob - Cook Top (1).rfa. on the countertop.
If my plan view is set to 'Hidden Line' I can see the sink unit but I can't see the cooker hob. Upon testing this is apparently due to the fact that the tap/faucet stands higher than the back of the countertop. If I remove the tap/faucet from the sink unit Family, then I can't see the sink unit either. I have checked the elevation of these components and they display ok in 'Wireframe'.
I have replaced the countertop with a worktop - Worktop.rfa so that both sink unit and cooker hob display as expected in the 'Hidden Line' plan view.
Ummm... is there an actual question tht i am not getting?