Revisor gets stuck at "Display Configuration".
 

I am trying to create a custom CentOS image using Revisor. After going through

# Basic Configuration
# Boot Loader Options
# Network Configuration
# Authentication
# Security Configuration

configurations, it gets stuck at Display Configuration. None of the options or tabs on "Display Configuration" page are enabled and nothing happens on clicking forward. I am unable even to figure out the problem. Can someone guide me how to proceed with this?