Thanks for reporting this. The issue has been fixed in version 2.3.1. The gain slider now restores the currently applied value when the popup is closed and reopened. Please update to the latest version and let me know if you experience it again.

Edit:Thanks for the detailed follow-up. You’re right: version 2.3.1 fixed the gain slider, but the popup is still not restoring the UI state for Pan, Equalizer, Mono, and Flip L/R, even though the settings remain active. I’ll fix the state synchronization for all controls as soon as possible in the next update. Sorry that the initial fix was incomplete, and thank you for reporting it.

Update: This has now been fully fixed in version 2.3.2. Pan, Equalizer, Mono, Flip L/R, and the Equalizer panel state are all restored when the popup is reopened. Thanks again for the detailed report. If you notice any other issues, feel free to reply here or open an issue on GitHub: https://github.com/tropicaddons/sound-adjuster/issues