Dual-State Button As Radio Button:
Variations on a theme...
Unfortunately, its not possible to look at the file as it is created with a newer version of the Nextion Editor (v0.31). Current release version is (v0.30) from your website: http://nextion.itead.cc/download.html
The V0.31 has been released on the website:http://nextion.itead.cc/download.html