Problem with StageWebView: keyboard not shown on iPad when needed

i have iPad2 (ios 6.1) application that uses stagewebview to show login pages. All of sudden it started to work incorrectly - when stageWebView shows web page with input fields and i tapping input field to enter text - i dont get system keyboard

Just nothing happens, cursor blinks but i am not able to enter text. It was ok some times ago in the same application, can it be after iOS 6.1 upgrade?

Please help!