While working on mobile application, we got one problem - scrolling within the app was working fine, but if there is text box within the app with text scroll does not work.

Basically you have to keep in mind that it is mobile app, and scrolling with 1 finger will scroll the whole screen, but the it is multi-touch device meaning that if you scroll with 2 fingers on the text area you will be scrolling within the box.

So scroll has nothing to do with the app, it is the way multi-touch screens (or touch screens on mobile phones) work.