Hello!
I’ve got the same problem. WP 4.7.4 (Linux), Firefox 53.0 (Linux Mint). I’ve tried with Google Chrome 58.0, but still I see the initializing surface. In behind I can recognize my page.
I’m using a Graphy-child theme. I’ve copied onepage.php to the parents theme, to solve the problem that I wasn’t able to enable Onepager. I’ve tried to copy onepage.php also to the child theme folder, but nothing happend, the initializing surface doesn’t disappear.
How can I solve this problem to use this great plugin, which I can test without any problem on the onepager-site https://getonepager.com/ ?
Thank you!