Webbrowser control not support proper Mobile Version Website

Question

I am researching about WebBrowser Control for Windows Phone app, I found one problem, that is, as Mobile version website opens in Internet Explorer of Windows Phone, that not get opened properly on Windows Phone app containing Webbrowser control.

Take Example: On Windows Phone Store there is an app "????????.???" It Used the Mobile version website (www.jeevansathi.com), Try to open same webssite in Windows Phone's Internet Explorer in that left top side corner there is menu Button, That worked properly on IE of WP but in that app its not working? Why is it so?

Why Mobile version site not open properly in App's Webbrowser Control???