When I write click on a zip file and extract it to a USB flash drive, there is no progress indicator but it it is working because I can’t unmount the drive because it is “busy”. Eventually I can umount the drive.
Progress indicator should be shown by the archive manager you use, not by pcmanfm-qt. It’s like you say, “pcmanfm-qt doesn’t show the progress when I’m seeing a video file on a USB flash.”
Sounds like you’re using Ark. Are you on Lubuntu? I don’t know if it’s an Ark or a Lubuntu problem, but I’ve also noticed the PCManFM-qt integration is somewhat lacking.
Since they switched from file-roller, I’ve resorted to just doing it in the command line instead.
So it is an Ark problem?
Not necessarily. If it’s running a command, then the command is not required to give any indication of its progress. I would assume they’re aware of the lack of progress indicator, and I would assume it’s non-trivial to add support. You’re best filing a ticket on Lubuntu’s bug tracker, as they would be able to figure out if it’s an omission in Lubuntu or Ark (or both).
lxqt-archiver will be ready for use with the next LXQt release. It shows the progress on extracting archives: