on ^*:hotlink:*//*.*:*: { }
on *:hotlink:*//*.*:*: { run C:\Program Files\mozilla.org\Mozilla\Mozilla.exe $1 }
on ^*:hotlink:*www.*:*: { }
on *:hotlink:*www.*:*: { run C:\Program Files\mozilla.org\Mozilla\Mozilla.exe $1 }

However, that doesn't allow for a right-click to open in a current browser, a new tab, or anything like that. It only opens a new window on double click. Still though, it works. That's what I use.