I remade the VIs following your new explanations (the first version was mainly to show how to manage the windows, not for parameters because it really depends on your app specifics from this point of view).
Anyway, I think this one is much better and it allows you to manage parameters easier. MAIN calls FIRST and FIRST calls SECOND after loading default values from file.
If you need to run the 1 and 2 separately, use VI server's "Set Control Value" method.
Regarding the values storage into file, you have several options: saving as text, binary, using configuration files or even the registry ... it's your call. Take a look in lv folder\examples\ or search on NI's site.
Good luck !
p.s.:
- regarding the sequence, it was probably just
to force the dataflow
- regarding the FP flash, I couldn't notice on my computer ... maybe you set the FP to open when called