A very old thread I know, but this may help someone else.
I was trying to use Pretty Print to format some MSOffice XML (from a PPT template that had been renamed as a zip). My initial attempts didn’t work “Nothing happened”. I eventually solved the problem when I realised that it wouldn’t work on files still stored in the zip. Notepad++ could read the files and displayed them as 2 looooog lines so I assumed (wrongly) that I could Preetify, edit and write back. In retrospect I should have realised that this was never going to work as the “file” I was working on was a temporary copy.
Solution: Extract the file from the zip (as opposed to view the file in the zip without extracting properly) , Preetify (which worked of course), edit, save, copy back into the zip overwriting the original.
An interesting corollary: Using the Windows Explorer zip functionality to open and view the contents (as opposed to extracting them) which uses a rather long temporary folder prefix - Pretty Print didn’t work.
Using 7Zip which uses a much shorter temporary folder prefix - Pretty Print did work. Obviously, I was still working in a temporary copy which wouldn’t get saved back.
