I need to obtain a list of selected files by the user on all the opened windows
i think I could use a system dll call, but no idea of which could be,
and Microsoft documentation is so sparse…
any idea?
All open explorer windows, even ones that are private and have nothing to do with your app? That seems like an odd UI experience.
What I need is to intercept selection changes, and only in the frontmost window and for a given file type
Best I could find on it “launch an Explorer window and watch the program track the folder you’re in and what item you have focused”
It might be easier to implement a file explorer into your app 
@Giulio Mastrosanti I don’t think that relying on an external application (which might not even be running) is a wise choice.
To be honest, I am not familiar with Windows, but I think it would be better to create a script/command usable from the Explorer to send the current selection to your software.