How does the act system prevent you from progressing like you say? The "list" command is mainly for convenience. It's there to remind you what scenes you have found. You could do the same thing by writing down the filenames on paper.
You can re-visit a scene by typing in the name again. The list command just makes it more convenient by allowing you to click on the name instead.
By only showing the files from one act at a time, it just causes unnecessary annoyance and confusion.
btw, the "act" command is pretty much useless, it only allows you to rename an act. I never used it. ("title" on the other hand was more helpful by allowing you to remember what happened in each timeslot.)