What is Quirks mode in Windows Phone?
The Windows Phone Apps that was targeted for Windows Phone 7.1 (Mango) runs fine without modification on Windows Phone 8.
There are some scenarios where the Windows Phone 7.1 App might behave slightly different when it runs on Windows Phone 8.
In this case, the Windows Phone app platform provides a mode called “quirks mode” that preserves this kind of behaviour and lets the app to run smoothly without any issue.
