Zebra Data Wedge reader multi screen behavior


I'm developing a mobile app to be used in hand held bar code readers. The app consists of several screens.

Now I want the user to be able to scan bar codes independent of which screen is currently displayed. I have tried adding one Zebra Data Wedge reader to each screen but then more than one triggered upon a scan. I have also tried to have only one reader, but that does only trigger when the screen where it is located is visible.

So, how does the Zebra Data Wedge reader work with multiple screens?

I know I could use multiple readers and disable all that is not on the present screen, but certainly would prefer if possible to use only one reader.

Any hints are much appreciated