QT4: Touch is not working if we touch on screen which has no touch action assigned

Hi All,
I am working on a QT widget app for an embedded linux application. In this app my first screen is welcome window with a graphics view and a label and none has a touch action handler assigned. I move to next window when required Hardware setup is done for my application such as timers and UART. Now I see a problem in my touchscreen where, when we touch on welcome screen, the later screens are becoming unresponsive to touch once we move to them. Can anyone provide some insights what could be reason for this behaviour?
I am using Emcraft IMX6ULL board with poky linux and QT4.

Thanks.