Possible bug:
As it is now in the Release Version (1.7.3) and the Beta (1.8.0.502) if you have Paragraph > Flow Options > "Justify Vertically" turned on and the text flows from text frame 1 to text frame 2 and you would have an orphan without "Prevent widowed last lines", the text at the bottom of the first text frame does not go to the bottom as it should to be "justified vertically." If you shut off "Prevent widowed last lines", the text is justified vertically as it should be, but now you've got a widowed last line at the top of the next text frame.
I don't want to put the file up publicly, but I'd be happy to share it with developers. Is there an address to which I could send a link so the developers only can download the file and check it?
Or maybe they can just duplicate the problem themselves without my file.