Are they really blank ? did you do a fit in window?
How are you activating the sections? From the project map or the view map?
Please add your AC version and OS to your signature.
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"