My Internet Preferences - File Helpers were set to Post-Process with Application (StuffIt Expander). Next to installing the Deputy Browser Plug-in, they became to View with Plug-in (Deputy Browser Plug-in). But, when I removed the plug-in by the supplied application, my helper settings messed up; they became to View with Plug-in (Default Plug-in). I had to restore Internet Preferences file from backups. This is possibly Deputy's dangerous improvement in recent updates!