The Website with the problem: Dentrist.com
The following video explains it all: https://drive.google.com/file/d/0B3I1u2C6pdwmb3lMQ0lkbkZoRGc/view?usp=sharing This same result appears on Android and Apple devices.
I've tried to fix it and find the div which is causing this problem, at least that's what I believed. Thinking that it was a CSS problem. But now I think its caused from the new Polymer (web components) I'm using on the site. Using Debug I found that when pointing on the tag/element "body" or "html" it marks all the screen. One thing to notice is that the selection of any link or text is working perfectly, following the entire page marking for some reason. I don't know how to explain it in other way.
Please help ! Thank you.