Mono Game 3.6 Windows Phone 8.1 Game touch issue on big resolution Devices

TouchPanel.DisplayWidth = 480;
TouchPanel.DisplayHeight = 800;

these lines of code fixes the touch issue.Thanks

I have another issue related to wp8.1 monogame template. Sometimes game screen freezes and does not allow to anything and when we press windows key then press back key game start working.

Can you please tell me how can i fix that freeze issue?