Startup settings are set to "open the listers that were open...". That used to work, but no longer. Am using version 12.17. Now I have to backup and restore settings to get the listers back to where they were.
The startup setting only applies when Opus is not already running. (Opus usually runs in the background once started, unless configured not to.)
You probably also want to turn on:
- Preferences / Launching Opus / Default Lister / Update Default Lister automatically when closing a Lister
That will mean each time you close a window it is saved as the new default.
Then anything which opens a default lister will open the same thing that you last closed.