A Please update the application to the latest version and try the following.
If your purchased rights for the Pro Upgrade got reset, please try to restore them using the following steps:

1. Log in to Microsoft Store with the same Microsoft account you used when purchasing.
2. Check your purchase history in Microsoft Store.
3. Click the gear icon on the title screen of ibisPaint to open the Settings window.
4. Click the "Restore Purchased Rights."