Update a global when going to a stack as modal

[Mark Powell]

I have a handler in stack A of the pseudo form below
  ...
  LINE 1 <put "Before" into global gFoo>
  LINE 2 <go to stack B as modal; user input there goes into gFoo>
  LINE 3 <put gFoo into fld "Information" of stack A>
  ...

The text that is put into the field on stack A is inevitably "Before".
However, if I immediately type 

  put gFoo into fld "Information"

the data that was collected in stack B is put into the field in stack A as
expected.  The global is populated as I would want, except it is as if line
3 above is run before line 2.  What is going on?  Can I not switch between
stacks and collect data?  Is there a workaround?

Mark