Web Dynpro ABAP - Sharing Data between two Windows

I am supporting a WEB DYNPRO ABAP application that was developed using two windows, with each window containing 1 view. The second window is a "popup" type window. I need some data that is generated in the second window/view to be available when control is returned back to the first window/view. How can this be accomplished ? ( I am brand new to WD ABAP )

Thank you

Larry