WinSysClean automatically optimizes your Windows System by optionally removing temporary/unused space wasting files, unused and invalid registry locations, invalid shortcut links, and many more.
such an option would confuse most of users and some registy entries are complex even for advanced users. eg. I don't think you will manually search in registry OLE/DCOM class id links which points to missing entries in order to confirm the removal of that entries...
There is an option to fix and repair Internet Explorer's favorites. Other browsers should be supported here as well. I commend your support for Firefox in other parts of the program.
The developer should uninstall the program, run regedit, and search for WinSysClean and keep on repeating 'find next' until it says finished searching registry, note all remaining entries and then set the uninstaller to remove these as well!