The process is to define a view and place it as a drawing on a layout sheet. Defining the View determines active Layer Combination and preview area two settings.
It sounds like you may need to redefine some of your views. To check this, select one of these 'empty' drawings on a layout. Right click and choose Open source view. Do you still see nothing?
Erika
Architect, Consultant
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
AC5-18
Onuma System
"Implementing Successful Building Information Modeling"