If your plugin does not make any changes to the file currently displayed in the preview panel, then it will not refresh automatically, you'd have to force it to refresh, by doing:
self.boss.gui.preview.start_refresh_timer()
after the call to
apply_container_update_to_gui()
Or you could just wait for the next release, where I have apply_container_update_to_gui() do that automatically.
https://github.com/kovidgoyal/calibr...136e9a0fdd5192